This is the code behind http://scottstuff.net/books/. It talks to bookstore websites and extracts information about upcoming author events, and then exports them, in aggregate, via RSS and iCalendar files.
In its current state, it’s probably not very useful to most people, but I’m making it available on the off chance that anyone wants to adapt it to their own use.
It requires a Postgresql database. See schema.sql for the schema required.