Just dropped my Galaxy S2 off at Carphone Warehouse to have the screen replaced. Quite impressed, £80 including parts and labour, and will be done by tomorrow lunchtime.
Couldn't find the screens cheaper that £100 online (ebay included, and fitting excluded), and doing it myself would void my warranty, this way I get it done properly, keep the warranty, and save money. Triple bonus.
So if anyone manages to break their screen like I did then would recommend giving them a go.