Backing-up Apps without computer

I've got an iPhone 4S and I want to obtain some sort of file that has a backup of all the apps that I have now on my phone, so that when I get a new device I can easily copy that file into my phone and it'll be exactly how my phone is now.

How do I back up my apps without the original computer?

And then how do I transfer that backup onto my new device?

Cheers!

(Not the most technologically savvy person in the world, so no clue as to whether what I am asking is reasonable or not...)