Lucas Jellema has written an article called "Getting Started with EJB 
3.0 Persistence out-of-container using the Reference Implementation 
(GlassFish) <
http://technology.amis.nl/blog/?p=962>," which shows 
step-by-step how you can use the reference implementation to persist 
data with EJB3.0 persistence, including a service class and a data model.
It's good to see people documenting their experiences with the various 
containers; now we need to start seeing use cases and things that 
/don't/ work with EJB3, so we can start building guidelines for when it 
should or shouldn't be used.
Merry Christmas