Over the past few weeks, Microsoft (NSDQ: MSFT) has kicked off a no-holds barred campaign to promote Bing, its new search engine. While most of the hullabaloo has been focused on the PC, the company is also moving the brand into mobile, where it faces steep competition.

Most notably, the company has rolled out the brand on Verizon (NYSE: VZ) Wireless’ network as part of an exclusive five-year deal it with the carrier to provide search and advertising services on the phone. Microsoft was rumored to pay $500 million for the opportunity, which was likely necessary given that Google (NSDQ: GOOG) and Yahoo (NSDQ: YHOO) dominate the rest of the U.S. wireless market.

The match-up was announced in January, and Microsoft started rolling out search to subscribers in the past few weeks. So far, many subscribers are currently accessing Bing from Verizon’s portal page, and through high-end browsers, such as Opera, where it’s the default engine, Microsoft said. Later this year, it “will be preloaded on the majority of Verizon feature and smartphones,” according to a spokesperson. Microsoft’s GM for mobile media Charles Johnson told Bloomberg that in the first 20 days as Verizon’s default search, Microsoft’s handled 19 million queries, or 10 to 15 times the previous rate.

Not only has Microsoft been aggressive about rolling out the so-called “decision engine” for mobile, it has also made progress on the advertising front. Microsoft has signed a deal with Hyatt to put the hotel chain’s ads on Verizon phones, where users will be directed to the hotel’s mobile web site.

Scott Howe, corporate VP of Microsoft’s advertiser and publisher group told Reuters he expects mobile phone advertising to be a significant opportunity going forward and “five years from now mobile will be 5 to 10 percent of media spend.” Howe cautioned it won’t happen all at once: “The question is when does it really hit mainstream? That’s probably still a year or more away.”

In addition to Verizon phones, Microsoft has launched a Bing for Mobile client for Windows Mobile phones, and of course, people can go to m.bing.com from any mobile browser, including the iPhone and Android phones. Microsoft declined to say whether it was developing applications for those two platforms, however, it did say that the current Blackberry and Sidekick apps will be re-branded to Bing from Live later this summer.

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