There's this group of fresh hip young things from the UK. They have released some actual play (I think they do improv or something too) of Mornington Crescent which really helps get the feel of the game. They've been recording their stuff for a while so there's a reasonable archive too.
@ Hal don't worry! They don't do rpg so I'm not going to be sending punters off to competing sites
Their stuff is avaliable on iTunes store and audible.co.uk for a reasonable price.