Samsung Galaxy s2 black. Excellent condition. Will swap for iphone 4/4s !

I have a Samsung Galaxy s2 for sale or swap. It is black and is in excellent condition not a mark on it. It is only 2 months old as i got it on contract. It is on o2. Will swap for a iphone 4 or 4s. Has to be at least 16 gb memory. Or £260