I do not use any special tools. It is mostly manual work. For Tiger I also made a few scripts that remove what I consider superfluous (plus they activate the hibernation mode, install the proper display extensions etc.).
For Leopard, I will eventually make them as well, but I do not have them yet.
there's a tool/app that does this (strips out the other languages, fonts, etc that you dont need), I forget what it's called, but it's free, and very good, accurate too. I need to strip down my mac mini before I do my car install.