There's two parts to building pedals. There's the skill of physically building and the knowledge of the electronics themselves.
You can learn to physically build pedals by building pedal kits, or doing clones based on schematics. There's a ton of resources for that sort of thing. The most important will be your soldering ability. Don't worry, it's not that hard to solder well enough to make things work.
Knowing what the components do is a bit more complicated. Unfortunately, you'll have to just learn it. Best way is to google. Wanna know how transistors work? Google "Transistor", and go nuts. Same with resistors, capacitors, etc. The most dumbed-down sites are places like howstuffworks.com. Wikipedia can be a great resource as well, but very hard to understand at first. It gets a bit technical.
http://www.beavisaudio.com <-- absorb this site. The tech section is GREAT. It has a great tutorial on soldering, as well as a few pages on how some parts work in pedal circuits.
I'm thinking there should be a "How stuff works-- stompbox edition" thread here. Like the DIY info thread. Or maybe just a series of posts in that thread?
One of my favourite sites, that I've never seen linked, is
http://www.allaboutcircuits.com . It has nothing to do with pedals. It's all about the individual components and how they function. it cleared up a lot of mysteries for me. Most pedal-based sites don't explain what's really happening, just what happens to the sound.
That's basically how I did. Research, trial and error, etc. Maybe not what you wanted, but there ya go. I'll be glad to maybe help explain some simple circuits to the best of my knowledge if it helps you out. Just let me know what you're interested in.
