Powerlifting belts

[androgenie]

I'm getting ready to take the plunge and sign up for my first powerlifting meet....but I'm really curious about the use of belts.  I'm wondering about the pros and cons of them, suggestions about sizes, brands, proper use, anything that would be useful for a novice competitor.  I've been lifting heavy off and on for years, but I'm getting to where I want to compete (ok, part of that is from seeing my state's rankings for women and I routinely bench 5x5 what some women lifted in competition).

Any suggestions for a novice competitor?