Wirelessly posted (iPhone 3G 16GB: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_2_1 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5H11 Safari/525.20)
You can create an alias and give that email address out instead, but you can't change your main (login) account name.
As for eBay, people just sell the code. You can buy it cheaper on Amazon, too.