How to tell sex of Savannah monitor?

I have a 2 foot Savannah monitor that i'm interested in breeding, but i'm not sure if it's a male or female. My friend said it's a female, but I wan't to double check :D. It's about 3 years old, super aggressive, and a awesome eater.
Here are some pics:

http://s401.photobucket.com/albums/p...1708131056.jpg

http://s401.photobucket.com/albums/p...1708131112.jpg

http://s401.photobucket.com/albums/p...1708131130.jpg

I was gonna get a pic of her underside, but she's way to aggressive for me alone to flip her over and take pics. Any info would be great and also pics of males and females would be awesome because then i can compare mine to the pics.

Thanks,
Ariel

Take a profile picture of the tail base.

If it is only 2' at 3 years old........it is extreamly small.