I suggest you take a look in rec.music.makers.builders. We just had a
thread on this subject last week over there. Are you planning to build
electric or acoustic guitars or both?

A couple of merchants that specialize in tools and materials for luthiers:

http://www.stewmac.com
http://www.lmii.com

These are good places to start. Remember that Google is your best
friend too. I've obtained a lot of tools, wood, and other supplies from
Ebay sellers as well.

Here's a website that I found extremely useful while I was building my
first couple of acoustic guitars (I started about 3 years ago):

http://www.hoffmanguitars.com/building_a_guitar.htm

I've also put pages on my web site that document to varying degrees the
construction of several of the instruments I've built over the last six
years. Start here for an index of these projects:

http://www.cyrguitars.com/music_page.html

Hope these things help! If you have specific questions, feel free to
email me privately, or post the questions on rec.music.makers.builders.

--Steve