Custom Text tones...

My understanding of hacks and such is limited, and I've been looking around but haven't found much, yet, on the topic.

You know the monty python "*twang* Message for you Sir" clip from Holy Grail? Would love to have that as the tone when I recieve a text.

Is there any way of doing this?
Secondly, is there any way of doing this that doesn't involve Jailbreaking?

If you can point into the right direction, that be great.

 

You know, it's late, and for some reason searching here didn't occur to me
Sorry bout that,