This link is floating all over the net but I discovered it over at Matrixsynth and I'm passing it on to you...yes, you (stand still would ya). Anybody who's into or makes music undoubtedly knows that there are a million and one sub-genres and classifications of music that help pigeon-hole the sound and style into one particular bracket or another. For the most part, it's not necessary to know the difference between hardstep, techstep, or darkstep drum and bass, but alas Ishkur has graphically broken it down and clearly drawn lines and separated the sub-genres (some of which I've never even heard of) and made it much simpler (if not more confusing) for the masses to understand complete with audio examples of each style. My personal favs are Booty House, Ghetto Tech, Florida Breaks, and Nu Electro. Check it out and school yo'selves on a muggy Sunday afternoon.
Ishkur's Guide To Electronic Music
And on a similar note, you should also check out DISCOGS which is a user-built database of music releases and discographies, and it's the mutt's nutts for hunting down track listings, albums names, production credits, and whatnot.