iTrip - just get em off ebay mate - make sure u get one thats based in UK mind cos loads of em are in USA/Canada and charge loads for postage & take ages to arrive!
I got mine direct from the manufactuer with the £ strong against the $, l got mine inc postage for £30 might be cheaper than ebay not sure though... Griffin Tech If you wanna check it out
if you get the in car charger with it you can get it really cheap compared to getting them both separately i think... careful if you get it thru a proper company in the US... alot of the time you have to paying import tax, which can be a bitch!