If anyone is looking to get the iphone 4S, Vodafone have an offer on where you can get £59 cashback if you preorder. Haven't looked at it in detail, but I think it applies to existing customers too.
You can also get an extra £40 cashback through Quidco, so £99 off in total isn't bad!
You can also get an extra £40 cashback through Quidco, so £99 off in total isn't bad!