There was a pressing need for a tut like this. So I stepped up... drop me a link if any good comes of this. Oh, and thanks for the many other tutorials that taught me enough to develop my own techniques..
--- EDIT: August, 2008 Why on Earth did I cuss so much? I was such a vulgar 13 year old when I made this. hehe.
Woah. Okay, had a try of this This is way better than some of the other comet tuts I've seen! Not that I've seen all that are to be seen mind you, but this produces much more believable comets. Looks great, thanks for posting the tutorial (yeah I know, like 3 years ago... I'm just getting into this stuff now...)