I wanna be an EJB Cowboy baaaby

Sorry for the Kid Rock ref ;) I am tired though, of not knowing EJB's. I've just not had the exposure to them. Some people would consider me lucky in that respect (i.e. Spring supporters). But it would be nice to fill in that area of my knowledge of J2EE. I know servlets, JSPs, MVC frameworks, some design patterns, and all that stuff, but never got a chance to use EJB's. Seeing as how my division here at work loathes databases it's not hard to see why. We've been storing everything on mainframes and using it as our data repository. I suppose I could jump right over EJB's and go for Spring. However, since I've never used EJB's I don't know how bad they are. Maybe if I learned them, then started to hate them, I would be more motivated to learn Spring. Anyways, EJB experience look good on a resume though right?

So I guess what I'm asking is where do I start? Stateless session beans seem to be en vogue, as well as message driven beans. Obviously MDB's require some messaging framework to be in place so I can probably rule that out for starters. Stateful session beans require persistance and therefore a reliance on databases. Wonder if I could do a CICS transaction mapping to a SFSB? I can probable call CICS transactions from an SLSB just as I do now. Maybe I should start there...

Anyone have any thoughts for an EJB beginner?