If you've been looking for a new ESB, you might wanna note the fact that MuleSoft is providing free training for the open source ESB, Mule. I don't see Oracle or Spring Integration doing that...
There's also some simple videos posted here if you're not up for the hands-on just yet.
Here's the training link Introduction to Mule ESB
and here's the Enterprise Free trial and the MuleStudio community edition.