Our API directory now includes 88 project management APIs. The newest is the Trajectory API. The most popular, in terms of mashups, is the Basecamp API. We list 14 Basecamp mashups. Below you'll find some more stats from the directory, including the entire list of project management APIs.
Need to get organized but fearful of the hairball of project management applications? Breeze, started by Rene Vahtel, offers tools that take nearly zero time to understand, so you can focus on the results for the project without getting bogged down in learning how to use the planning tools.