Do you need something like Fitnesse, if you have BDD tests?
JBehave (and NBehave recently added the same support) work with regular test files so while many other frameworks add "BDD taste tounit tests" the text based behaviour specifications/examples created with JBehave are suitable for acceptance tests. And no, you don't need fitnesse for that.
To get an idea of how it works I suggest JBehaves 2min tutorial.