Welcome from another Texan, the best way to find out about comps in Texas is one of 2 web sites.
The first is IBCA...the International BBQ Cookers Associationhttp://www.ibcabbq.org/
go to the Events tab and then select 2009 and you will see all the sanctioned events for this year. I know the next one coming up is Snookfest in Snook.
Another good Site is the Lonestar BBQ Societyhttp://www.lonestarbarbecue.com/home.htm
Again, find the tab that says 2009 Events and go from there
Good Luck and hope to see you at an event