When you have full root, you most likely have a custom recovery. OTA updates rely on the stock one. Most likely, it will reboot, and just get confused, and do nothing but get stuck at a black screen. Pulling the battery just takes you back to Android. That is not *always* the case. Sometimes it really screws things up. If you rooted with unrevoked, you *can* flash the stock recovery, then accept an OTA update. That is *not* recommended. If *anything* goes wrong, you won't be able to fix it until a root exploit is found. A better idea is to follow the instructions in the Rooting for Dummies guide - section 6 under after rooting. If you're referring to updating to the latest OTA, now, I still recommend you follow those instructions. You *could*, however, unroot or flash a stock recovery and update, as unrevoked works with all current OTA updates. That is still not recommended, though, as it will update your hboot version. If you have any nandroid backups, they will be useless if your hboot version changes.