MyBB (or any other forum) - display as view

[eluser]peter222[/eluser]
I'm looking for solution how to integrate any forum with existing application (existing layout and user database).

I found this http://phpdave.com/MyBBIntegrator/

Looks ok, but I still don't know how to embed this script in my application (existing header and footer)? I need to put it in my third_party folder?

Run as library? Call simple like this: http://myapp.com/mybb? but what about htaccess?
I can see nothing in documentation about existing third_party folder. I don't want to do it by iframe. So, cUrl is good idea?

Maybe other forum script will be more easy to integrate?