Snarl is a notification system for Windows inspired by Growl for Macintosh that lets applications display nice alpha-blended messages on the screen. Snarl is all about displaying notifications. The notifications may be displayed on-screen in a variety of shapes, colors and sizes; they may be spoken out loud; they may even be forwarded to a web-based notification environment, your mobile phone, PDA, or another computer. Snarl does this by acting as an intermediary between the application creating the notification and the end user and, because Snarl provides a standard API for the sending application and a standard user interface to the end user, it makes it an incredibly powerful tool.
Some examples of what Snarl can do:
Notify you when your laptop power supply has been disconnected or the battery is getting low.
Receive notifications from a central server.
Forward notifications to your iPhone, Windows Mobile phone, or Android phone.