There is a software program out called Tournament Builder. I have used it and does a great job.
They have a limited-free version but does up to 16 teams, you may want to check them out. It's called tournament builder express (If you do a tournament with this software you'll need to make sure it does auto-seed otherwise you'll get a funky bye)
http://www.sportsmvp.com/tools/tbexpressDL.php/
There is also some software out there called Matchmaker. does a great job on single elim tournaments but does some funky things with byes and double elim