If you are referring to your Sprint e-mail address, as in what was assigned to you @SprintPCS.com you are able to change it. You can chat in and state that you would like to change it. Just inform the agent of what you would like the e-mail address to be and it will be whatever you choose @SprintPCS.com.
Have a good day : )
Brittany is right, you are able to change it...There was a typo in mine and I got it changed. However, the Sprint rep I did an online chat with said I was unable to change it. I emailed customer care and they changed it right away. As with all customer service at any company, it depends on who you get.