Creating Message Boards using Flash

I know there is a Flash Forum Engine on the market currently but the financial hit is way out of hand. (1000 Euro or about $2000 US) Seriously?!

Anyway, does anyone know what I need to do to create a Flash based Message Board?

I would like to tie the forums into the user accounts when the person logs in but also have a visitor be able to log in.

Think standard forum.

Any help?