i would like to add a forum to my site , is there a program that can do this for me ? ive tried forumupuk or something like that ...but i want to be able to put my own ads , affiliates etc on the forum..can anyone point me in the right direction?

Take a look at phpBB or Simple Machines Forum. These are two great forum packages which are free.

I've had good success with SMF and they just came out with a new version with a much nicer default skin than their previous one.

Placing ads can be a little tricky for someone who isn't fluent in PHP coding but the SMF forum has some very helpful volunteer developers than can assist with it.

I am currently using phpbb and it's ok
if your host has Fantastico you can install phpbb from there with no effort at all