Well we heard officially last night that ASUS was going to start pushing the Jelly Bean update to Transformer Prime (TF201) users today, and it seems that the rollout is now in full effect. If you haven't been notified of the update yet, you can check in About tablet > System Firmware Update, and then wait for the download and install. Users report that the reboot can take a while -- so do your best to be patient while the update does its thing.
Having issues or want to share your experience with the update? Hit up our forums and see what everyone's talking about.