[[http://tigoe.net/pcomp/resources/ | This is Tom's mega pages of resources]]
I have added some or repeated some of his here that are my favorite.

[[http://jasonschlauch.backpackit.com/pub/39671 | Here is a list of surplus places]] 
*http://www.allelectronics.com and http://www.goldmine-elec.com/default.htm are good places to browse in order to get a sense of what is out there.
*A buddy of mine (Chris) works at this electronics supplier: http://www.sparkfun.com (a very very good resource for components, parts, pcbs, new cool stuff etc.

Computers as Theater Brenda Laurel