running a process when a directory or its contents change
 

I would like an rsync process to be executed when a directory, its subdirectories or contents are modified. I'm not sure the best way to do this. I could put an entry into the cron and have it run every 2 minutes or something but that seems a bit excessive. The directories may only change once per day but when they do they need to rsync. Any ideas?

A quick look on google gives some ideas:
http://www.devchannel.org/devtoolsch.../2146252.shtml