Web and EJB Tier Transaction Guidelines

For web tier:
Web Tier Transaction Guidelines

For EJB tier:
Web Tier Transaction Guidelines

A guide about J2EE transactions
A developer's guide to EJB transaction management

JNDI object lookup in a clustered environment

In a clustered environment, it's safe to look up a JNDI object using local reference. For instance, if the JNDI name of your JMS queue connection factory is jms/myConnectionFactory, configure a local reference so that you can look it up like java:comp/env/myQueueConnectionFactory.