Mike, you might try this url for a crawfish pattern. Casey Smartt (Gartooth) is a really good tyer, lives in New Braunfels, TX (or somewhere close). He has several good patterns, and while I haven't used this one yet, it does look good and I don't think too difficult to tie. The Backwater Hawg website has a bunch of good flies for other species, types of water , etc.
http://www.geocities.com/clinscott_pfl/bwhgpage3.html