There is a module to pull in legacy content, but you'll have problems
integrating it. You're better off just going with something like Active
forums. I run DNN 2.1.2 and 3.x with forums and they are nowhere near
as good as WWF, but they are easier to maintain and I didn't have to do
any additional programming for them.
http://www.activemodules.com/
Sorry Bruce, but I'm just lazy. If you had a DNN version, I'd switch in
a heartbeat. WWF are way better, but using them with DNN is too painful
to bear