Today: New iPhones, a sweet Android deal and Microsoft's $7.2 billion takeover of Nokia's phone business show mobile war is still alive and well on a strong day for Silicon Valley stocks.

The Lead: Apple, Microsoft, Google and Verizon make moves in mobile

The revolution in mobile computing devices that has been raging for a decade is not dead yet, as several technology giants made moves seeking to stay (or become) relevant as PC sales dwindle with consumers using smartphones and tablets for most of their computing needs.

Apple (AAPL), which lit the initial spark of the mobile era with the introduction of the iPhone in 2007, is expected to show off its newest iteration of the popular device at an event in Cupertino next week. Confirming earlier reports, Apple on Tuesday invited media to an event at its headquarters, where the tech giant is expected to unveil two new iPhone models at once for the first time: A lower-cost iPhone housed in plastic instead of metal that many expect to be offered in multiple colors, and a continuation of its main iPhone line that may also offer multiple color choices, including a gold iPhone aimed at the Chinese market.

After the introduction of its most recent smartphone, the iPhone 5, last September, Apple stock hit an all-time high of $705.07, but it has struggled since, falling as low as $385.10 as analysts and investors grew impatient with the lack off innovation at the Cupertino company that rolled out the iPod, iPhone and iPad in the past decade. With the expected introduction of two new iPhone models and a trade-in program designed to keep consumers coming back to Apple smartphones, the company is seeking to counter that trend, leading analysts to predict the event could be an important milestone in Apple history.

"The next event will arguably be the biggest product launch in Apple's history because it will tell us about the future of the company as a true innovator," IDC analyst John Jackson recently told the Mercury News.

Apple stock rose 0.3 percent to $488.58 Tuesday.

The PC giant that Apple left in its dust in consumers' eyes made its biggest move to fight for mobile relevance late Monday night: Microsoft announced that it has agreed to pay $7.2 billion for Nokia's mobile phone business, combining two formerly dominant tech giants. Nokia was the leading cell-phone manufacturer for 14 years, making analog phones that sold well worldwide until smartphones became more popular; Previously just a software company that licensed its products to hardware makers, Microsoft has moved into hardware with its own tablet and now a smartphone business.

"We know we need to accelerate. We're not confused about that," Microsoft CEO Steven Ballmer said in a conference call Tuesday. "We need to be a company that provides a family of devices."

The purchase of Nokia could have an ulterior motive: Ballmer recently announced his impending departure from the company, and the purchase includes Nokia CEO Stephen Elop, a former Microsoft executive who was already seen as a candidate to replace him.

Investors and analysts were not impressed by Microsoft's deal, however: The company's stock declined 4.6 percent to $31.88 on the day, and many analysts questioned the wisdom of purchasing a company that has fallen so far in popularity.

"The question is whether combining two weak companies will get you a strong new competitor -- it's doubtful," telecommunications consultant Paul Budde told Bloomberg News. "Both Nokia and Microsoft really missed the boat in terms of smartphones, and it is extremely difficult to claw your way back from that."

Google (GOOG) made a similar, but more expensive deal, for Motorola Mobility two years ago, paying $12.5 billion for the hardware company. The difference is that Google already had a successful mobile platform, which it reinforced with Tuesday's announcements that 1 billion Android devices have been activated, and the operating system will have a corporate partnership for its next version.

Android chief Sundar Pachai made the twin announcements Tuesday, and Hershey's backed it up with a news release announcing further synergy as Android Kit Kat rolls out.

While speculation of a paid branding deal circulated, Google quickly shot that down, explaining that the partnership had nothing to do with profits.

"This is not a money-changing-hands kind of deal," John Lagerling, director of Android global partnerships, told BBC.

Android Kit Kat is expected to debut this fall; Google typically launches a specific device to coincide with each new version of Android. Google stock gained 1.6 percent to $860.38 Tuesday.

Android is far ahead of Apple in smartphone market share, with one manufacturer, Samsung, shipping more smartphones than Apple and smaller vendors such as LG snagging a significant share of the market. While relegated to the "Other" category in IDC's most recent smartphone shipments report, Nokia placed second in total mobile phones shipped.

Big news was not relegated just to companies making smartphones: The largest wireless carrier in the United States, Verizon Wireless, was involved in a huge deal over Labor Day weekend. The company, begun as a partnership between Verizon and Vodafone, was taken over completely by Verizon in a deal that will ship $130 billion to Vodafone.

SV150 market report: Yahoo stock gains as new executive arrives, new high for Netflix

All the merger action on the long weekend juiced investors to push stocks up, but gains were tempered by possible combat in Syria. Silicon Valley stocks weathered those fears well, however, as shares in local technology companies gained 0.8 percent, better than all three major U.S. stock indexes.

Yahoo (YHOO) gained 2.4 percent to $27.78 after officially announcing the arrival of former AOL executive Ned Brody as the chief of advertising for the Americas. The Sunnyvale-based Internet portal also reportedly shut down its Yahoo China site, which was pushing readers to a site owned by Alibaba, in which Yahoo still owns a significant stake. Netflix (NFLX) reached a new two-year high of $290.71 and closed with a 1.8 percent gain at $289, as the Los Gatos video-on-demand company continued to rise.

Silicon Valley's major solar companies headed in opposite directions, with San Jose solar manufacturer SunPower (SPWRA) gaining 3 percent to $22.13 and San Mateo solar installer SolarCity plunging 5.9 percent to $29.49, its lowest closing price since May. The other company in the SV150's green energy sector, Palo Alto electric car maker Tesla Motors (TSLA), hit a new all-time intraday high of $173.70 Tuesday, but ended the day with a slight, six-cent decline to $168.94. After tremendous gains on the backs of their earnings reports Friday, Salesforce and Splunk again hit record highs Tuesday: Splunk moved 3 cents higher to $55.24 and Salesforce gained 0.9 percent to $49.58.

Up: SunPower, Juniper, Electronic Arts (ERTS), LinkedIn, Yahoo, Pandora, Workday, Symantec, Netflix, Google, Zynga, Facebook, Gilead, Salesforce, Yelp, Cisco (CSCO), NetApp, Applied Materials, eBay

Down: SolarCity, Palo Alto Networks, Tesla

The SV150 index of Silicon Valley's largest tech companies: Up 10.47, or 0.82 percent, to 1,293.03

The tech-heavy Nasdaq composite index: Up 22.74, or 0.63 percent, to 3,612.61

The blue chip Dow Jones industrial average: Up 23.65, or 0.16 percent, to 14,833.96

And the widely watched Standard & Poor's 500 index: Up 6.8, or 0.42 percent, to 1,639.77

Check in weekday afternoons for the 60-Second Business Break, a summary of news from Mercury News staff writers, The Associated Press, Bloomberg News and other wire services. Contact Jeremy C. Owens at 408-920-5876; follow him at Twitter.com/jowens510.