how to make a guitar tone stack?

im making my own amp, but it occurred to me that i'll need gain, bass, mid, and treble controls as well. i know these are generally part of the preamp but i cant seem to find one that is simple, with few parts (small opamp , 4 or 5 pots and some caps/resistors). oh yeah if you could show me a site that carries all the part too thatd be nice, becauseive always used all electronics, but thay seem to be lacking... they dont even carry a 250k pot!

I'll give you 2 rather simple stacks with mods to change the target amp sounds.
1st is runoffgrove's Tonemender at This is pretty much as you ask with an opamp and a few passives.
2nd is a Solid-state Fender Blackface Preamp from Redcircuits at This uses 4 FET's and a handfull of passives.
Either will do what you want. The big factor in choice will be your supply voltage. The Tonemender is designed for 9V operation while the SS Fender Blackface is designed for a range of 18-30V.

As for stores/sites for your components, most of the big names have what you are looking for. Try Mouser and Digikey (as seandogue suggested) as well as Jameco and MCMElectronics. There are more out there, but these are some of the biggest.

Have fun, and let us know how you fare.