Hi,

I'm about to hold a live questions and answers session on my website, and I'm trying to decide on the right software / technology to host it on.

Do I use a forum like phpbb,
or one of the many ajax chat style apps available.
I've had a look at some meeting room software, but i think it's a bit over the top.

Any opinions?

Use a chat room. Flash chat at tufat.com is 5 bucks.

For a cost effective solution, you could always open a chatroom on one of the many public IRC servers out there. :)

I'd agree with that. A lot of times live QAs will be held on an IRC server. You can get a Java client which you put on your website which connects to the IRC server, saving the need for your users to get mIRC or like programs.