MUGGSY I use Gee on both my home and work computer. Both run system 10.3.9, my home box is my trusty old B&W G3 (upgraded quite a bit) and my work box is a G4 Digital Audio. Gee checks the mail just fine on both boxes, but on the G4 I cannot access the any of the menu bar functions.
I love the program! It's a great boon to those of us who haven't yet upgraded to 10.4.
(Version 1.1.2)