storm-growl provides a bolt implementation for growl notification. It receive "title" and "message" from previous bolt/spout and send it to growl.
storm-growl requires libgrowl. You can download it from http://sourceforge.net/projects/libgrowl/
You must set up growl can "Listen for incoming notifications" at "Growl" in "System Preferences". (for Mac users)
For old versions
You can get storm-growl for old storm versions. https://github.com/tjun/storm-growl