Want to track my banner

i would like to know where do i get start to build my own tracking banner ad system. I just want to track the banner click that send back to us.

I know there is open source openx, but wanted to see if there any easy open source out there.

As of now, i have tracking with google analysis but want to see any good open source out there.

You should check out Piwik. http://piwik.org/
It looks pretty good as an open source alternative to Google Analytics.

It really depends on how simple you want to go. OpenX is more powerful in the long run.