There's also a bunch of websites out there that offer tools to play with as well. I've never played with any of these myself, but people I know say they're pretty good.

Open Source Forensics
Linux Forensics
Local Area Security
FIRE
Snarl

Most of the above have ISO's for bootable CDs, so if you've got a broadband connection, a burner, and a spare computer sitting around, download a few of these and play around. One of these days, I'll get around to doing the same. Also, report back and tell me how they are...

Alpha