If he's more than 6 months old, all you have to do is hold him in your hand, lift his tail up and towards his head. Basically form his tail into a big U. Then look at his private parts. If you see 2 bulges, he's a boy, if you don't, he's a she.
Beardies are pretty easy to sex after about 6 months.
Hope to see you there. I'll wear my "I own snakes and I vote" t-shirt.
Jim Smith