According with BGR, Google wont make any agreements with any wieless carrier by the time Google launches its new phone, the Nexus One. Here is an internal photo saying T-Mobile will support many features for this phone but, it will only be sold my Google ( via web ) .
Google, with support from T-Mobile, is scheduled to launch a new Android device in early January. The Google Android phone will be sold directly by Google via the Web.
Support for the device including troubleshooting and exchanges will be managed by Google and HTC. T-Mobile will offer service support including billing, coverage, features, and rate plans. Additional details Streamline content regarding the launch of Google’s Android phone will be coming in early January.
Maybe T-Mobile will sell this phone around March, but this is just a rumor.