I have a great excel spreadsheet that does all the calculations you could ever need. Very easy to use. PM me with your e-mail address and I'll send it to you.
As far as a tutorial, there's not a lot out there. For a basic car setup though, it's pretty simple, pick your slope, your crossover point, add a zobel network, then your L-Pad. The L-Pad is the trickier part because that's extremely dependent upon in car response and where the speakers are actually located. So that's pretty much trial and error to get it right. I like variable L-Pads just for that reason. Parts Express sells them, if you use 8 ohm drivers. 4 ohm variable L-pads are a little harder to find, but I can help out with that too, if you need.