Can I change my Apple ID?

Apparently I'm not asking the question correctly so I'll try again. When I got my first iPod doc connect with scroll wheel, I had to setup an apple id. So I used the only email address I had at that time which was my internet provier. So if I made a purchase I would get a receipt there. Now, when I no longer use that internet provider is there a way to change where I get receipts for my purchases? I realize in order to update my apps in iOS 7.0.3 I need to use that original login. Now, if you don't understand what I want please ask and maybe we can work through this.

Thanx