Tracking Who Logs In

We've setup a profile page that users can login to and edit using Newspublisher. The client wants to know when users login to this profile page so that they know the profile page is updated. With over 100 users, filtering in the backend using the Manager Log isn't practical. Is there a way to perhaps email site administrators when these pages are edited or when people simply login on the front end? Or is there a way to generate a report?

You should be able to accomplish this functionality with a hook (http://rtfm.modx.com/display/ADDON/Login.Using+Pre+and+Post+Hooks) and/or using a plugin tied into one of the security states (OnAuthenticate perhaps?)