dead strip on iphone screen! help!

They should just replace the phone. I have been through a couple now and any sign of a fault they just replace it. Aslong as it hasn't got any obvious signs of being dropped or water damage (Little white thing in the headphone socket turns pink) then you shouldn't have any problems.

Usually takes about 10 -15 minutes for them to sort everything out. They check the serial numbers swap the sim cards so you keep your original. This part is great because they use a special "Apple Tool" for removing the sim card which is actually just a paper clip in a plastic bag but makes me laugh every time! Then they register the phone or something on there system. When you get home you will have to fill in a couple of things in iTunes again like your email address and phone number I think from memory and thats it all done.

So, can we assume from this last post that you have hacked the phone? If that is the case, then you have done something that voids your warranty. Apple may/may not replace it. Their policy is not to replace if you have modified the phone in anyway. The process of modification could have caused the problem, in their view.
If you have not modified the phone, and just cancelled the contract, and are only using the non-phone/data options of the device, the issue would be the reactivation of the new device. The other options will only work if the phone is activated.

Wow! That seems unusual. But yes, if you intend to take it to an Apple Store, it is better to make an appointment. If you don't, you have to wait for all of those people that have made appointments before you are served.