According to a news release from the companies:

"BlackBerry smartphone users will be able to use Microsoft Live Search as their search engine of choice within the BlackBerry Browser as well as access Live Search on Mobile.BlackBerry.com. Live Search will leverage the wireless data optimization capabilities of the BlackBerry solution to deliver results quickly while users are on the go. BlackBerry smartphone customers will also be able to use Live Search to perform contextual, location-sensitive searches or look for nearby points of interest from inside BlackBerry Maps."

Microsoft already had a beta version of its Live Search for BlackBerry. It looks as though the new arrangement with BlackBerry, set for availability later this year, includes deeper integration with RIM's browser and maps. (Update, 9:03 a.m.: The existing Live Search for BlackBerry is a client application, which has been available in a final beta version since October 2007, a Microsoft spokeswoman told me via e-mail. The new development is indeed a Web-based version of Live Search.)

The move is a substantial distribution opportunity for Live Search. RIM sold nearly 5.6 million smartphones in the second quarter, giving it 17.4 percent of the global market, research firm Gartner reported earlier this week.

Microsoft has been pushing for such distribution deals -- such as the exclusive one it inked with Hewlett-Packard in June -- as a way to promote usage of its search service, which trails Google and Yahoo and has struggled to maintain its own share in the last two years.

While Microsoft would not disclose terms of the deal, Live Search on BlackBerry is not exclusive. Google, too, has worked to improve its search performance on BlackBerry phones in the U.S. In June, it rolled out updates including blended results (web, local and news search results on the same page) and related search suggestions on mobile search results pages in the BlackBerry Browser. (Update, 9:12 a.m.: Google also released a Mobile App for BlackBerry yesterday, promising "faster search and easy access to Maps, Gmail, News, and more from Google.")

On another front, RIM is a top Microsoft competitor in the mobile phone operating system space, along with Symbian, which runs Nokia phones.

Still, Microsoft and RIM have found other areas to collaborate. The search deal follows a similar agreement reached in May to make Windows Live online services usable on BlackBerry phones.