Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Even if back in August 2005, www.gnome.org/bounties/Mailer.html#127516 said the status of a bounty for implementing a panel notification applet for new mail in Evolution is "Solved", even to date, Evolution 220.127.116.11 does not have anything for showing in GNOME's notification area an icon when a new mail arrives! The real solution is evonotify.
The only caveat is that Evonotify has quite a lot of Perl dependencies, the most important being "Gnome2::Wnck" and "Gtk2::TrayIcon".
Here's the synopsis of the major Perl packages you'll need: