Ok, saw a lot of confusion and assumptions here and in the Evo main forums about how to get this update and how it affects both rooted and non-rooted users. Let me explain briefly:
If you're rooted, do NOT attempt to get this update via OTA or manually. Like EarlyMon said, at best, you will lose your root status. At worst, you probably know what's the worst case scenario.
What you need to do is wait for the announcement of the rooted version of this OTA. It's typically out within a day of the official OTA but sometimes it even beats out the OTA if the OTA was leaked in advance. Keep checking this "All Things Root" subforum for updates on this rooted stock ROM.
As for bootloader issues: irrelevant to everyone. Anyone rooted already has an unlocked bootloader. If you flash the rooted version of the OTA, your bootloader will remain unlocked. If you are NOT rooted, your bootloader is currently locked (but not unlockable). By going through the process of rooting your phone, you will unlock the bootloader.
Finally, if you are thinking of rooting your phone in the near future, do not accept this OTA. There is no known root exploit for this ROM since it is new (AFAIK
. I could be wrong), so you can't root from 2.3 yet. Root your phone while it's on 2.2 (or 2.1) because the exploits for these versions are tried and true. Then simply flash the rooted version of the 2.3 update.
I deleted some posts in this thread in anticipation that a lot of people are going to be seeking info here. Nothing personal; just trying to stay organized. Let's keep things on topic and keep the speculation (new Sense, e.g.) to a minimum, please.