Just like anything related to sexual behavior, it *can* enhance orgasms. Not everyone likes it (just like anything else), but for those who do, it can significantly add to their pleasure, or even produce a whole different type of sensation and orgasm.
I'd recommend starting with a tried and true toy, like any of the Aneros. If you've never had anything up your bum, I'd start with a lubed up finger, to see if you even like it.
And remember, as with all anal play, lube is freaking crucial!