Adding Panel Notification for New Mail in Evolution
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 22.214.171.124 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: