Free Resources

http://www.soundhack.com/freeware/ - a great collection of free plugins for VST/AU/RTAS, Max and PD

freesound.org - Copyright-free samples from anyone and everyone anywhere ever. Bliss!

dontcrack.com - Brilliant site for a huge array of audio software - much of it free. Great for VSTs

Audacity - the brilliant free sound editor

http://mda.smartelectronix.com/effects.htm - free and open source Mac compatible VSTs

Spear - free spectral analysis and editing software