Warner Onstine's book on Tapestry 4: Tapestry 101 is now available!
Tapestry 101 is a great introduction to Tapestry using real-world examples. It goes beyond just using Tapestry components and dives into integrating Tapestry with Spring and with Hibernate. It's organized around a real application implemented in the small and should go a great way towards filling in the gaps in people's Tapestry knowlege.
It's available right now as a downloadable PDF.