adding posts from outside wp acp

Hello,
I want to kind of integrate wp with forum, when you add topic to forums, there to be additional fields to add wp post from there.

I noticed WP does a lot more then just updating content and title tables in database with new post, and I don’t want to corrupt wp database by adding incomplete info to it from outside script.

what procedures must be completed to avoid this? I mean what are the necessary tables in database that must be filled in for post entry to work properly?

I’m trying to figure out stuff like this on my own, but with so many included files I find it hard to understand how all this works together or what does what. I’m not php expert 😛

thx in advance!