Have Apps with Notification Center Support Use Growl on Lion I'm still on Lion, and recently noticed that a lot of my apps are being updated with Notification Center support. Since I'm not on Mountain Lion and therefore don't have Notification Center, I won't be able to use these new features. However, I do have Growl, and was wondering if there is some tweak or hack that I could use to forward these notifications to Growl instead. Thanks in advance!
For Mountain Lion

Hiss goes the other way (sends Growl notifications to the notification centre in Mountain Lion).

Growl 2.0 is on it's way and they've developed a new piece of code they call MIST which will send notifications:


to Growl if it's available; or 
to notification centre if you don't have Growl.


This means if app developers use this code instead then people still on lion won't be unsupported.
Read more here http://www.macrumors.com/2012/06/13/next-version-of-growl-to-add-notification-center-support/

Update to ML when you can, it's awesome.

For Lion

I don't think there's anything (right now at least) to turn notification centre alerts into Growl alerts.