Nexus One by Google only sold by Google

Taken from Google's Press Release:

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.

via: BoyGeniusReport