Yakov Shafranovich has written a script to convert tracking data from FedEx, UPS and USPS to a RSS feed.

Currently support is provided for UPS, Fedex Air and Ground, and the US Postal Service (USPS) via a set of XSLT templates and a Perl wrapper. The page at SourceForge is for demo purposes only. You are encouraged to download the code to implement on your own.

If you have an e-commerce system that provides tracking data to customers, this would be a nice added feature.