It was shuffling ok last week, and I can't remember if I've had any updates to the programme or to my system since.
It plays a song then stops.

You know how it is when you do things automatically then can't think how you did it when you try to explain it?
I think I use the right arrow key to skip to the next song - and that doesn't work either.
I've got iTunes 9.1.1 on OS 10.6.3
I double checked that I haven't got the skip option ticked.
Any ideas?