There are a wide number of forums that serve the anti-creationist movement or in which science and creationism can be discussed. Many tend to have ups and downs.
At the moment (September 2006 the Yahoo email forum at http://groups.yahoo.com/group/creation_evolution_debate/ has some lively debates but we have to say that whilst the anti-creationists there are smart, the creationists are mostly mind-numbingly daft (they usually are).
Lenny Flank's forum at http://groups.yahoo.com/group/DebunkCreation/ is more strongly moderated and has fewer creationists in. They rarely hang around long in any case. Flank is clever because he sets the agenda for the debate in simple terms - no preaching, no religion and no cut and paste. Creationists have difficulties complying with such simple rules.