This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
If you are serious about load testing I would suggest LoadRunner or Performance Center from HP. Additionally, HP offers Service Test which is a functional testing tool for SOA that creates tests that can be used with LoadRunner to do performance testing. These tools are not cheap, but they are best of breed.