Here's a very good (and rather old) call-in interview with creationist Kent Hovind from the Infidel Guy show. Several important points for debating creationists may be gleaned from this:
1. Setting up a format similar to a conversation is a good idea. With some debates, one guy gets 20 minutes to speak, the next guy 20 minutes, and so on. This is a bad idea, because creationists can throw out more baloney in 20 minutes uninterrupted than an Oscar Meyer factory in overtime. But if you can stop and discuss the issue, and pursue it to the conclusion, then one can see that creationism does not hold up. Listen to the way Hovind gets backed into corners in several instances.
2. If you debate a creationist, know your topic. Think of every possible objection the creationist could make (Be familiar with your opponent's views and look at your arguments through an opponents eyes). You can see that Hovind's opponents have done this, especially the guy who called in about Carbon Dating.