I recently upgraded to 1.2b3 and switched from CDROM+Floppy to an IDE 
hard drive.  Since then between 1-2 times a day the m0n0wall firewall 
locks solid.

Anybody else seeing similar problems?

To attempt to troubleshoot whether it was the upgrade to the switch to a 
hard drive I have switched back to running from CD, still running on 
1.2b3.  If I continue to experience lockups I'll go back to 1.2b2 on CD, 
just in case it's hardware.

Are there any other troubleshooting or diagnostic steps I should perform?

-- 
Q. How many Microsoft technicians does it take to change a lightbulb?
A. Three. Two to hold the ladder and one to hammer the bulb into a faucet.