i could no longer use OS X, because it kept booting the computer up in an invalid range and i couldn't see the OS to change the resolution. The mac has handled this kind of thing far more elegantly than Windows for at least a decade - to revert to this kind of unintuitive behavior is just inexcusable.
in any case, i could not do a thing to make this work. zapping the PRAM no longer resets the monitor values to a default like 640x480, and disconnecting the monitor, shutting down, booting, shutting down, plugging in the monitor and booting didn't do it either. After asking around on another BBS, i was able to get the system back. deleting the file:
/Library/Preferences/com.apple.windowserver.plist
while in 9.2 and rebooting into X worked fine. It inherited the settings from 9.2, and i'm now working from 10.1 again.
-perry
December 20 2001 Update: An alternative method of solving this problem is to restart with the shift key down during a reboot - this seems to now indicate to OS X "reset the monitor at startup" instead of "disable extensions". This solution courtesy of this thread on the MacNN forums.

