There are only three options I know of.
HCCP runs on a computer. I used it last year and I'd say it's a bit older, sometimes glitchy, and has a learning curve (I suppose they all do, but learning glitches is less fun). Entry info must be manually entered or imported through CSV files.
BCOE&M (which Darkside mentioned) is very popular, but it's web based so you'd need server space to install it. Big advantage though, judges and entrants enter their own information. Many competitions, including NHC, use this. brewscene.com
is a newcomer that I'm interested in. I'm pretty sure its free and it has a couple dozen competitions in it's past competition list. If you want online (I would unless its a very small competition) and don't have server space, I'd check it out.