I'd say probably some of the best ways to find out about tournaments is either 1) ask your instructor or 2) out of any martial arts magazines. If you have any friends that are also taking martial arts ask them or their instructor. Once I've seen an advertisement for one at a bookstore, although only that one time.
I know how you feel, it's hard for me to find out about tournaments as well. I recently went to a Tae Kwon Do tournament and I found out about that from a friend's friend at school.
Anyway, hopefully I gave you at least one good suggestion. If not-sorry >.<
p.s- even websites can help you out for listings in your area.
:asian: Your bother in training.