Hailing from Melbourne (Australia), Mal Webb is a world-renowned vocal gymnast, multi-instrumentalist and singer-songwriter.
When live he has a loop pedal that allows him to record a loop live and then sing/play over the top of the loop. Watch this YouTube video for an idea.
Aside from solo performance he is also well known for the many bands he has been involved with - most notably Totally Gourdgeous, Oxo Cubans and Bomba.
Lots of his songs are available free as MP3 on his Myspace and his website: http://www.malwebb.com/
"You're a freak" said Ani DiFranco of Mal (really!)
"He's like Bobby McFerrin, Aphex Twin and Cole Porter playing scrabble" - B.Freely