Joyce Davis of IBM Lotus LTIE fame reminded me about a wiki article on developerWorks that contains 26 exercises that can help get you started with XPages development.

From the abstract: 

These workshop exercises are designed as an introduction to Lotus Domino's xPages functionality. To give you a complete learning experience, you will build a demo application in the course of completing the exercises. The result of a previous exercise will be needed as input for following exercises. 

Some of the exercises do not directly contribute to the sample application, since they are designed to highlight and explore functionality and capabilities of xPages not needed in the sample application in all variations. These exercises are typically followed by an exercise that implements a subset of the function in the sample application. 

Note: To be able to complete the exercises you will need to consult the documentation for Lotus Domino development since information given in the documentation is not duplicated in the exercises. 

 Check out the entire wiki article at http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Tutorial-intro-to-XPages.htm