Here's a couple links for you:

http://www.pythons.com/probing.html

http://www.pilbarapythons.com/sexing.htm

http://www.corn-utopia.com/Corn%20Ut...h%20Probes.htm

http://www.dewsburycrafts.co.za/prob...structions.htm

As each site mentions, probing is something that you really shouldn't try doing all on your own without having been shown by someone with experience first. It's not like I've done it myself, but I know I wouldn't want to risk causing any damage and depending on the willingness of the animal it seems to be a two person job anyway.

Hopefully a more experienced member will live in your area and be willing to show you how... If not, perhaps there is a local breeder who would be willing.