Help adding dynamic advertisement?

Hello all.

I would like to add a different banner to each of my large number of pages, based upon the type of page it is. What could I put at the top of the page, in place of the picture, to call and place the picture there? What should a PERL script for something like that look like?

Thanks!
yoshi http://www.datera.com

Here you can find many scripts that do just that: http://cgi.resourceindex.com/Progra...Advertisements/