There are two software products that you can use, but I'm not a big fan of either actually. Casino Verite v3 has a tournament mode, which was removed in v4 pending a new tournament special version of CV. If you have CV4, the CD ships with the old version v3 as well, and you can install both versions to get the tournament features.
The other software is Wong's Tournament Blackjack. It's OK, but still not all that great.
I'd recommend playing online, either free games at (Dead link: http://www.playubt.com) or paid games at Bet21.com. However, all those games use the special UBT elimination format with some extra twists. Still, it would be reasonable practice. Just realize that free games feature MUCH more aggressive players than you'll see in a typical tournament.