Haha, my Cossie has developed a fucking horrid screech lately, but it's a familiar one, loose power steering belt again.

With a bit of luck yours is just loose too. I think the adjustment bracket is a poor design, hard to get it as tight as you want it.

EDIT: saw you said it was smoking, so yes maybe seized.

Look on the bright side, loud sudden noises accompanied by smoke from under the bonnet can be REALLY expensive, or they can be something like a dodgy power steering pump, I know which I'd prefer