- Open this link on your phone but https://market.android.com/search?q=google+wallet when asked to open in the browser or market, click on browser.
- Click on the Google Wallet icon and, when asked to either open in the browser or market, click on market.
- Install and enjoy!
P.S. Apparently this is supposed to work on all carriers. I'm only on T-Mobile so I can't validate this.