Hi Colesworthy:

I think that cindygallop's answer is great – pure advertising may not necessarily be the best way for you to go. But if you do want to go this way, there are several well known aggregators that will make it easier for you to add advertising to your site:

Google AdSense – this is the probably most common and easiest to integrate, though not necessarily most profitable. Check it out @ http://www.google.com/adsense/, start with the tour.

Yahoo Publisher Network – Yahoo's version of the same. Check it out at http://publisher.yahoo.com.

You might also want to take a look at Federated Media Publishing, founded by John Battelle. It works somewhat differently than Google AdSense / YPN, and it seems quite interesting. Check it out at http://federatedmedia.net/.

I hope this helps!

Ayelet