I'd love to know what sort of infrastructure you're running this on. I'm in a course for my Masters for library school that deals with similar sorts of problems in maintaining and preserving for the "long term" digital materials.

From your site it sounds like you wrote a script using wget to harvest the files and another to check them against versions that were still up. What do you do on the server end now to ensure that the files are still working correctly? Are you running periodic checksums on them or the like? Finally, are you looking for any help from an interested novice?