Google is beginning to phase in over-the-air updates to Android 2.2 / Froyo to Nexus One users on T-Mobile and will continue over the next couple weeks.
If you'd like to install it now, instructions are right here. Root access is not required; just download the update, drop it on your SD card, and follow the instructions to start the upgrade: http://phandroid.com/2010/05/22/manually-update-your-nexus-one-to-android-2-2-froyo/
For those without a Nexus One on T-Mobile, I've taken several screenshots around the OS and in a few applications. Check them out here if you like, and feel free to ask if you'd like to see something else: http://www.flickr.com/photos/cscotta/sets/72157623991007169/show/
The "Chrome to Phone" extension for cloud-to-device messaging is also available here: http://code.google.com/p/chrometophone/
Have fun!