If I understand your inquiry correctly, you are seeking to find someone who will manage the advertising at your content web sites? This would apparently include mostly "affiliate links"?
Of course, you've omitted the most important information: what kind of traffic does your site draw, what is the site's topic, what kind of visitors do you get, and what are they doing at the site?
I'm not aware of anyone doing "affiliate-side management" but if you look at it as "advertising management" it may be easier to find someone.
If you truly are limiting your goals to affiliate links, then you should probably talk to affiliate managers at some of the companies you expect to be key partners, to see if they might be able to help you directly (for free) or refer you to an appropriate partner whom they recommend.
It may turn out that one of the "datafeed services" could meet your needs. Of course, some merchants (such as Amazon and AllPosters) let you create a variety of dynamic links that feature best-selling products within a specific category or theme.
Some affiliate managers can actually create complete sub-sites that you could plug into your site to promote a specific type of product or service.
[edited by: eljefe3 at 4:26 am (utc) on Sep. 19, 2006]
[edit reason] no url's please [/edit]