Someone may remember I constantly ask this whenever I start a new army, and I just started Tau. I was google imaging them to see what people had done with them, and I saw a Gun Drone with big red numbers on it. I clicked the link, and apparently this person has marked up what each part of a sprue is. I didn't get a chance to rip through it yet, but this is really helpful to me, and I'm not sure if anyone else needed it (or the appropriate place, but I figured this would be the best place for it). Anyways:http://www.cygnusx1.info/
There's galleries available, as well. I'm also checking out parts of other armies because nobody points at something and says "this thing, right here, this is a scatterlaser and can do a lot of low str shots into your infantry, avoid that with your ground troops". I have to do my own research because I don't want someone reading their codex aloud to me and slowing down the game. But enough ranting.
EDIT: OK, apparently he did the write-up for Tau only. Sorry about that. I should have put this in the Tau forums, I guess. But, it has some interesting info on other armies, including all the chapters for SM.