Web 2.0 API Directory
About once a week I get a question about if there is a Web Service that does x or y. (Usually something like Exchange Rates, or Maps) Here is a cool site I was shown that has a great list of Web Service Interfaces, some example mashups and what is required to use these services. :-) This is a pretty cool site. The range of Web Service API's out there made me laugh... My two favorites included one that gave the political disposition in Illinois and one that was for email marketing companies united against disposable email.... :)
Enjoy!