Google Wallet is great and with a rooted phone you can definitely use it on almost any device. I have the CDMA (Verizon) Galaxy Nexus and it works just fine. Anywhere they have the quickpass mastercard scanner thing. You see it as a little pad on top of the credit card reader. Anywhere you can scan you credit card without swiping you can use wallet.
You get $10 free from google for using it, the only problem is unless you have a certain mastercard, you have to load up money to a google gift card from another source ahead of time to use wallet.
It's not that big a deal since you can do it from your phone. It has a pin for protection to keep you secure, in case someone scummy enough to steal a phone has the mental capacity to know what google wallet is.
Has anyone used it with the screen off or while the app is closed? I have only used a few times and both times I'd already typed my pin. If you do it with the phone screen on but haven't opened wallet, it asks for pin right?
It's scary the first time you use it, I almost didn't believe it would work, but it DID!