SimpleMail uses the standard MUI appicon located in "MUI:Icons/def_MUI.info". You could change this icon, but all MUI apps that don't have an appicon will also use the same "def_MUI.info" icon.
I love SimpleMail, but wish that it would use a similar AppIcon scheme as YAM uses (e.g. showing an alternate appicon for new mail, and showing how many new mails are unread in the icon text)
