Sample information heaven
The-Breaks.com (formerly Sample FAQ) is a huge list of songs that have been sampled. Very strongly recommended. Essential.
Old school sounds
Phat Drum Loops This is probably the best place on the web for them old beats - you're going to spend hours there. This guy - like me - really loves drums. So should you.
Funk45.com - oooh what a place! Lots of RealAudio files of old funk songs. Go there now!
Original loops and sounds etc.
Loopasonic top drum loops, bass loops, guitar loops... Very, very good.
Weebl's Junk. Really tasty sounds, loops, tunes and a wicked site design.
Trommelundbass live drum loops
Record stores
Dusty Groove America sells records according to the name. That is, soul, jazz, funk, hip hop, soundtracks and so on.
Jump Jump Music has the same kind of records as the above, plus a section with high school bands - believe it or not.
Record companies
Ubiquity Recordings is the home of Ubiquity, Luv n' Haight etc. Hip hop and good reissues of funky stuff
Rhino. Good reissues of soul, funk, jazz, rock, etc.
ACE, a big reissue company
Beat Goes Public, reissues of funky jazz and jazzy funk, like Pucho & The Latin Soul Brothers and Houston Person.