pgnotifyd connects to a PostgreSQL database, listening for the named asynchronous notification. When notification is received, it executes the given command. It is typically a cleaner and more efficient alternative to polling a PostgreSQL database for changes (using a crontab(5) or similar.)
Instructions are in the man page provided with the source code.
The current release is pgnotifyd-0.1 (29th May 2010)
There is a Git repository:
git clone http://www.pogo.org.uk/~mark/pgnotifyd.git
Source code is distributed under a BSD license