Currently ROM Manager is using a recovery hot replace to give you a custom recovery. But I'll eventually be packaging this into ROM Manager's flashing process like the other phones it supports. I'll wait a week or so to switch, while everyone switches over to the new root.
For those that want to make ClockworkMod their default recovery on recovery boot, use this image:
These step assume you have already unlocked your NAND using the "Part 2" thread in the forums.
Place these files on the root of your SD card.
Then run this from a root Android shell.
cat /sdcard/flash_image > flash_image
chmod 755 flash_image
./flash_image recovery /sdcard/recovery-clockwork-supersonic.img