< body . bgcolor="#FF0000">
Put this code anywhere in your profile. Change FF0000 to the hexcode of the color you want your background to be.
< body . aolmailheader>< font . back="#FFFFFE">
Put this code where you want your white box to start.
Put < /html> where you want it to end. This will clear all of your font formatting, so you'll have to reapply colors, styles, alignment, etc.
Note: This only works on AOL 4.0 and 5.0, and you can't change its color. AOL 6.0 mail headers use tables, which don't work in AOL profiles.