I have been using Google Wallet for various online transactions but I've begun using it for retail transactions. Surprisingly I've found more establishments than I expected supporting NFC. When you check out, look for this symbol on the terminal.
Just a couple of examples of where I've found NFC are McDonalds, OfficeDepot, CVS, Home Depot, PetCo, Walgreens and even Local Express in Hernando.
It seems to require me to unlock the phone and input my Google Wallet PIN. McDonalds was blown away. They had never had anyone else do it. OfficeDepot still wanted me to sign the receipt.
There's still no NFC support on the iPhone but that may be coming.
It's early yet but I'm glad to see progress.