After posting earlier for info on how to change the user name, I happened to stumble upon it and managed to change my iPhone's user name.
It's as easy as ABC.
1. Just go into iTunes' SUMMARY page.
2. At the top-left-hand-corner, work your way down-"Library"-"Store"- and finally you will reach "Device" where you will see what you have entered as a user name. (The user name is flanked by an iPhone icon at the left and a battery & eject icon on the right)
3.Insert the cursor after where the user name ends and erase it. I used the 'back' key to erase, but the 'delete' key may also work.
4. Type in what user name that you would like to have and then 'click'. Your iPhone will respond after a 1~2 seconds delay to the click to initiate the change.
5. To confirm that it's changed, go to 'Settings' - 'General' - 'About'- and the new user name should be listed below 'General & About' and above 'Network'.
Hope this info is of assistance to anybody who might want to change his/her user name.