Udacity just (August 12, 2014) released an API that makes all of their course information easily available:
See the overview here: Udacity Course Catalog API
And the documentation here: Udacity Course Catalog API Documentation
Some other APIs that have online course data:
- Coursera has an entire "App Platform" including Catalog API
- Udemy has an API (version 1.1)
- EdX has an RSS feed of their courses (anand a full API on their roadmap)