Hiss is an OSX app that forwards notifications from Growl enabled apps to Apple’s Notification Center in Mountain Lion. Growl has been the popular choice when it comes to OS X notifications, and has a huge list of software that supports the app’s notification system. The app work’s, sucking in notifications from Growl-enabled apps like Sparrow, Spotify, and Adium, and dropping them alongside Apple’s.
You can get Hiss for OS X Mountain Lion free. Grab it now. 
