I just bought "Fuzzing: Brute Force Vulnerability Discovery" and skimmed it a bit. I was pleasantly surprised to see that Python is the language of choice for many fuzzing tools, and clearly the favorite language of the authors, since they implemented many of their tools in Python. See the fuzzing.org site/blog also, especially the Fuzzing software page. Sulley in particular seems a very powerful fuzzing framework. I need to look more into it (so much cool stuff, so little time.)
Update: got through the first 5-6 chapters of the book. Highly entertaining and educational so far.