http://www.youtube.com/watch?v=R2Mn6aczVNg
After contacting Verizon Global Services I was able to unlock my VZW TP2 today (for free) and pop in my European SIM. Supports my SIM PIN, can see all my contacts, and even supports short codes.
While this doesn't mean that at AT&T SIM card would work because it's supposed to be locked down for US carriers, it does show that US frequencies are available.
Enjoy, sorry I didn't show the Unlock.