I really don't see that this should be an issue. We shouldn't have to use third party tools to monitor changes to the website or have to check the changelog directory daily.
Just add an attribute to your existing AwareIM application on your website called LatestBuild, then when you create a new build, update this attribute and run a rule when LatestBuild WAS CHANGED that sends an email notification to all users advising them that a new build is available.
You could enhance this with a description of the build changes in the body of the email.
Pete