If you’ve been itching to use GrowlMail in Leopard, then look no further than the latest Growl beta, 1.1.3 Beta 4.
If you don’t know what Growl is, you’re missing out on an awesome Mac app. It is basically a system-wide notification app. It is highly customizable and supported by a lot of Mac apps out there. If you own a Mac, you got to have this.
Growl Beta download page here