Specific and Different Ads for each Post?

Hi @ewakened:

The simplest solution would be to have them upload the ads as photos using the media features in WordPress and then to have them add custom field called “Advertisement” with the URL to the ad copied from the media module, and a custom field called and “Ad URL” to link to the advertiser’s site. Then in the theme use the following to retrieve the add’s URL:

<a href="https://wordpress.stackexchange.com/questions/6267/<?php echo get_post_meta($post->ID,"Ad URL',true); ?>">
   <img src="https://wordpress.stackexchange.com/questions/6267/<?php echo get_post_meta($post->ID,"Advertisement',true); ?>" />
</a>

Beyond that is would be very possible to create a custom metabox plugin that would allow them to upload one of more ads directly into the post edit screen but that would require more programming.