It's not hard to setup your own forum, so I'd suggest getting some reasonably cheap webspace with MySQL and PHP support and then get some forum software running (i.e. phpbb or SMF).
Some webspace providers even offer forum installers (usually phpbb), which makes things even easier.
If you don't want to pay for webspace, there is also something like razyboard, but it's not that great IMHO.
Bye
Thanee