This article [link no longer available] speculates on whether or not Google has a mobile phone in the works. It would make sense for Google to do that, since Google now has a wide array of Web-enabled applications and services that would work nicely on a large screen mobile phone. The phone and its associated service might even be free or very low fee; if it was, Google would recover its costs by restricting what users can do on the phone and/or by interspersing ads with service access (you might have to view an ad to make a phone call or do a search).
Google is also likely to include GPS capabilities, since this would enhance its mapping and ad services. A phone with GPS could provide "you are here" capabilities when delivering a Google map, and the phone could also localize ads. As you walk down the street, your phone could beep at you to tell you that there is a Domino's Pizza a half block away and why don't you stop in for a personal pizza?
The phone will likely be popular with casual users who don't mind the intrusiveness of advertising, but a lot of people will not care for it.