It took a bit of doing, but the Android hackers at XDA-Developers have put together a downloadable version of Google Wallet that appears to work without a hitch on the Galaxy Nexus and Galaxy Nexus LTE. At least one user has also reported successfully paying for a Jamba Juice, so although there are still some reports of bugs, it's looking like it's worth a shot.
Whereas previous attempts were difficult to install and often resulted in app crashes, this version is a simple APK install — no muss, no fuss, and no rooting. However, if you've installed earlier attempts at Google Wallet on your Galaxy Nexus, you're likely going to be in store for both muss and fuss as you'll need to clean all that off before using this new version.
Of course, what would be ideal is if Google could find a way to allow users to cleanly and easily install Google Wallet directly from the Android Market, but given the amount of money and the complicated corporate politics involved, it's sadly not likely to happen very soon.