How does Growl work
Well when a man and woman get together...er wrong discussion. Growl. Right.
When an application (or script) wants to display a notification through Growl for the user (that's you), it sends the information to Growl. Depending on your preferences Growl will show the notification using one of the display plug-ins, speak it to you, email it to you, or even block it from going anywhere if you have Growl set up that way.
The application does need to support Growl for this to work. We keep a list of applications that work with Growl here.
A diagram of how Growl works.
The actual display of the notifications is handled by Growl, and the sending application can continue with what it was doing without thinking about it.
Now, on to installation!