You an me both! I took the plunge an rooted my brand new Droid 3 and can report that
I had no problems (I wish I could promise you the same).
I followed these instructions (
Pete's Motorola Root Tools ) exactly (using Windows 7, 64Bit) and it took literally minutes.
In general, flashing a recovery is something done after you have rooted your phone, as it generally requires root access to perform.
The exact steps I followed were:
Pete's instructions from the link above.
Once rooted, I opened the Market, and installed the free version of Rom Manager.
Opened Rom Manager and chose to Flash ClockworkMod Recovery.
Rebooted phone into recovery using Rom Manager.
Performed a nandroid backup in recovery.
Flashed the Liberty2.0 Rom