www.xmethods.net
This cool toystore of Web Services has quite a few public services listed. You can try them out via the client provided.

Not sure that there are any applicable to telling history, but some may show up, or it may inspire you. If you really want to play, look at ESRI's map services.

The Google service has a number of implementations you might find educational. Of those, Floogle is a tutorial/exhibit on using webservices in flash.