Is there any way to set up an affiliate program to market android or iPhone apps? Where I can pay someone in a given market space (say "cooking for diabetics") for each app installed as a result of their blog?
You're talking about creating a "pay per install" network. You want to look through the documentation on tracking referrers to the Android Market, which will allow you to give a site a unique link to use to promote the app, and allow you to track how many installs come from that particular referrer.
Appbrain.com have a pay per install advertising service, they advertise your App on their website and in their App and you only pay if the user actually installs the App. I believe this is android only, and you need to publish your app first and have a few ratings before they allow you to promote your App.