This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
If you want to have fault tolerance system you need to persist messages. For example JMS providers can persist messages into persistent places like file, db.. Very interesting solution is database-integrated message queuing functionality - Oracle Advanced Queuing.