Do you mean the BIS account icon. Are you using the Gmail program for blackberrys? If you are talking about the icon that shows up for each BIS account, just log into BIS and delete the account.The icon should go with it. Then you can use the gmail app.
I have an icon for rueters.com that I can't delete. I have check the applications menu and I can't find it and I tried going to the desktop manager and trying to delete it that way, but no go.