I don't know if you can get mail while the app is closed. I doubt it. However, if you are using 10.5 (leopard) why not just assign it a space? You could even hide the app so it's running in the background. That is what I do.
Mail can be closed with being quit just like iTunes, Safari, and many other programs. Why not just do that? It takes up approximately 0.1-0.2% of my CPU.
Mail can be closed with being quit just like iTunes, Safari, and many other programs. Why not just do that? It takes up approximately 0.1-0.2% of my CPU.