they're actually pretty simple. one of the cool things i learned is that a)most pedals barely have anything going on in them and b) they're MASSIVELY overpriced. the one i built was $60, but i bought 10x the parts just because there's a break on things like resistors, etc. it would easily be a $300 pedal regularly.
if you want a style of pedal, let me know, i'd be happy to do some more building... loved the process, i don't really need a bunch of them for what i have planned, just a good amp head at this point :)
guy i linked below has some of the best gear reviews... goes through everything.