ppc searchengine table layout

For the last few days I have been thinking of doing a pay per click search engine.
I've been trying to figure how i should layout of the mysql tables & colums
The more I think about it the more confuseing it gets.

So I was hopeing that somone would give me some ideals or maybe somone would
like to start a source forge project with me. or point me to a project already in progress.
or an example. I would realy like to do this I'm just am not advanced enough to figuare out the table layouts......