Just to let everyone here know, through the weekend, T-Mobile has this phone for $49, free after rebate, free activation and free over night shipping. I ordered on Tuesday and got it yesterday.
Once I got home from work, I took my AT&T sim and placed it in the Nexus and it worked perfectly with no changes needed. After rebooting, the phone was able to use data, send MMS and make calls.
This is a nice alternative for those who don't have $349 to spend for the 16GB because you end up getting it for free on T-Mobile and it's unlocked.