I personally use www.SimpleScripts.com for this exact reason. I use a ton of open source software for my websites and it is hard to keep track of all the updates made to them. SimpleScripts emails me every time an update comes out and it provides me a one click upgrade to the latest version for Wordpress, phpBB and Drupal which are the 3 systems I use the most.

I have been using simple scripts on my websites for about a month and I love it. This is a great article that shows why I love it - Version tracking and backups for a one click installer = priceless!