AT&T and Sprint 3G Nexus Ones In the Works
AT&T and Sprint look like they both may be working on Nexus One versions of their own.
At the moment, Nexus One only supports 3G on T-Mobile, not for any other carrier in the U.S. It supports AT&T Edge, but more variety is always a good thing. Nexus One has turned out to be a nice phone that promotes a great user experience.
Read more at Gizmodo
Google Nexus One Review: Best Android Phone in the U.S.

A two part video review of the leading Android phone currently available in the U.S., the Nexus One.
Android 2.1
Shortcuts/widgets make touchscreen navigation a breeze
3.7 inch brilliant, crisp display
Accelerometer (built-in)
Nice media gallery function
Visually interesting, easy to navigate, great user (consumer) experience
3G compatible with T-Mobile in the U.S. (only), but works on edge with AT&T
Good call quality
Social media integration
Trackball (which makes web browsing easier in some instances
Couple of downsides:
Android keyboard isn't the best in the business--not multi-touch enabled.
Part 2 Nexus One Review
Video reviews done by Noah at PhoneDog, a great place to find phone reviews.