I'm sure we'll be seeing something about Willie-palooza soon. There's also the Battle Of The BBQ Brethren but that's more towards the end of the summer.
If you have never entered a comp before a good way to get your feet wet would be to try a one day grilling comp like Grilling on the Bay in Brooklyn. The URL is http://grillinonthebay.blogspot.com and it will be near the end of March.