1. It goes by the date on the back of your Xbox360. Or if you save the receipt, it goes by the date on the receipt. They will ask you to send them a fax of the receipt if the console is out of warranty on the back but still under warranty from the purchase date. Seeing that you are in USA, if your console breaks cause of those reasons, the repair process is pretty simple for you. You will call them, or fill out a claim on their website. They will give you a prepaid shipping labell to print out and off the console goes. In less than 2 weeks you have another xbox360. But the odds of your console breaking are rather low as long as you have one of the newer modes (April 2009 )
2. The only multiplatform game that I can think of and is noticably superior on the PS3 is FFXIII. There are a few games which are noticably superior on the 360 (Orange Box, Bayonetta come to mind) as well but most of them are pretty much the same despite what fanboys claim. Like you wouldn't notice the lower resolution difference in Red Dead on PS3 unless you have a 60 inch TV screen...and a magnifying glass.
