As detailed in my August 15, 2008 post BackTrack 3, this suite of security, assessment, and penetration testing tools is all contained on a LiveCD, or if you're like me, on a bootable USB drive.
remote-exploit.org is plugging away at the next incarnation, version 4 of this most excellent toolset.
According to the Back|Track LiveCD blog, the upcoming version will include such gems as having a PXE boot system and the ability to generate WPA tables.
Back|Track is an excellent, portable suite of security tools. If you've been downloading single-use applications and tools, you might want to consider using this instead. It gives you almost everything you could possibly need in one CD or flash drive.