The good news:
OTA Rootkeeper (by the way, it shows up under V for Voodoo in your apps list) successfully backed up my rooting and temporarily removed it before the OTA process. It then restored it after the OTA.
The bad:
The OTA update didn't work. It downloaded the update package (B06 to B08), rebooted, went into "arrow-coming-out-of-box-toward-android-guy" mode, and failed. It happened so fast (I tried several times) that I couldn't see exactly what was going on, but I did see some hex and "update aborted" or something similar.
I'm wondering if it's doing a checksum on the existing firmware and, because I used Titanium Backup to "integrate updates of system apps into ROM," it failed. Unfortunately, there's no, uh, "disintegrate" option.
I'd like to try the "storage card updates" option, but I don't know how to get the package and what folder to put it in. I'm not excited enough about updating to use the through-Windows method and reinstall all my apps afterward - especially because I have two Warps to deal with. (Yes, they are backed up to Dropbox.)
Oh, and I updated the PRL and profile (whatever they are) and they seemed to work.