I get the message "This item isn't available by your carrier."
After upgrading to 4.0.4, it still doesn't work for me. I had Google Wallet on my T-Mobile Nexus S before I moved to ICS, but I haven't been able to get it back since.
Are there tricks to downloading this from Google Play, such as Market Enabler? Presuming you can trick the market into allowing you to download Google Wallet, are there any missing libraries which would prevent it from working?