Jeff Atwood posted an article about serializing objects in the web.config file a few weeks ago on his blog. I recently gave a presentation on creating custom configSections in web.config by creating custom SectionHandlers. One day I'll write it up and post it to here how its done. Until I get time to write that up, you may want to check out what Jeff has going on with creating an object, then serialzing it, and then storing it in the web.config file. Of course you could use app.config as well.
The most interesting nugget that came out of the comments was a reference...