Shoutbox

You can change your screen name but its a pain in the ass to do it.

Sign in to your gmail account in web browser
[ Go to Settings
Click Accounts TAB
Click Visit google account settings ] *
On the left nav click name and more
Change you first name and last name to your screeny (they wil show altogether ie firstnamelastname)

If you want your actual emails to be sent without your screename and back to you normal name

Go back to the accounts tab and click Send mail as
Change to a custom name



* or put https://www.google.com/accounts/EditUserInfo?service=mail in your browser