Well, it didn’t take too long! Soon after Google released the preview build of Android 4.1 Jelly Bean, ROMs are ready to install on your GSM Galaxy Nexus or CDMA Galaxy Nexus from Verizon. For the GSM variant, just download Android 4.1 ROM, do a full wipe, and flash the ROM via Clockwork Mod Recovery. A root fix and updated radio can also be flashed via CWM. If you have the Verizon version, download Jelly Bean ROM, do a full wipe, flash the ROM, and flash SuperSU.
The best thing about these ROM are since it came directly from Google will likely be bug free and give you stock Android 4.1 experience. User reports suggest everything works in order. Enjoy!