If you're having trouble finding services that will search multiple geographic locations, it's because Craigslist doesn't want you to do that. They want to keep it local. They've gone so far as to shut down services that offer multiple-area search, the latest being craigsfindr.com.

I think it's a little ridiculous myself. They now have so many cities on there that sometimes "local" might include three areas for you, and you don't want to go searching each one individually. On the other hand, I don't want Craigslist to get too national. I'm very happy that they do their best to squash cross-area listings, because most of the time it's spam or scammers.

Anyway, I think the founder of Craigsfindr is giving his code away out of spite, so you might have any number of tools pretty soon