Motorola and Google Align for Mobile Search is the official word from Google and Motorola that they are teaming up in a mobile search partnership. Motorola is to insert a Google button into "internet-optimized" phones beginning by the end of March 2006, worldwide. The button will take users to Google search services.
The BBC reports that eventually, Motorola will incorporate a Google link into all of its phones. Google has a variety of mobile search services, and Search Engine Watch members can read up on them via the Google: Mobile category in Search Topics.
Recently, Google released a special local search application for Java-enabled phones. It also maintains web and image search designed for mobile phones, including a more restricted index of mobile-friendly pages, along with SMS search features.
As for other mobile partnerships, Google has one with T-Mobile and way back in 2001 partnered with Sprint, though that might not still be going. I'm checking up on others and will postscript as appropriate.Postscript: Here's another mobile phone/web partnership. Sprint and Yahoo began offering an enhanced client for Yahoo Mail last June.