"retrofy your hi-fi system"
"AirCassette is a cassette player application for iPhone and iPod Touch. Choose your favourite cassette from a variety of nostalgic cassette models. The playing song information is written on the cassette label and you can also share your cassette view with friends on Facebook or via email."
more info http://aircassette.com/
since when have iPhone or iPod Touch or i-Anything been construable as "a hi-fi system" ?!
(cheers to rob cotter for tip off)