There's a rumor saying
Google is talking to Orange about a cell phone that is to be produced by HTC, the biggest producer of smartphones. What does that teach us ? HTC makes mostly hardware to run on Windows Mobile OS, so I think we can safely assume Google's celly will be a windows powered one.
The device would not be revolutionary: manufactured by HTC, a Taiwanese firm specialising in smart phones and Personal Data Assistants (PDAs), it might have a screen similar to a video iPod. But it would have built-in Google software which would dramatically improve on the slow and cumbersome experience of surfing the web from a mobile handset.(GigaOM)
Will it be interesting ? I think in a way yes, but if you look at the number of existing (smart)phones that can run Google's software (well, some like gmail,gtalk and such) already, they're looking at fierce competition.