Hardware

cre.ations.net
User based creations website with a focus on electronic hardware.
http://cre.ations.net/

Cryochem9's Grid
Mostly links to interesting hardware sources, but includes a message board and the like.
http://members.tripod.com/Cryochem9/grid1.html

Freedom to Tinker
Discussions on the freedom to understand, discuss, repair, and modify the technological devices you own.
http://www.freedom-to-tinker.com/

Hack A Day
A hardware hack every day.
http://www.hackaday.com/

Hacked Gadgets
A resource for DIY project documentation as well as general gadget and technology news.
http://hackedgadgets.com/

I-Hacked
Information about hacking internet appliances, game consoles, and palm pilots.
http://www.i-hacked.com/

Winston's Lego Computer
Estimate is that the components for this lego PC (including the adapters needed for the notebook hard-drive and CD-ROM) come out to $330-$380 not including Lego pieces.
http://home.hawaii.rr.com/chowfamily/lego/