The Attention Manager was a feature introduced in Palm OS 4.0 to co-ordinate information from different applications. It's not perfect though, and many users are annoyed by the fact that you don't get continuous alerts to things like new SMS messages or missed calls.
Attention Grabber is designed to change that, working as a hack for the Attention Manager. The main interface in Attention Grabber looks pretty dull, but it's functional and easy to use. You just need to set the program's state to 'Enabled' and choose the time interval between alerts.
You then get to choose how Attention Grabber will alert you, and can select 'Beep', 'LED' or 'Vibrate' (or a combination of these). You can also specify what time you want to activate the application, so it automatically comes into effect at this hour.
That's about it really, so Attention Grabber isn't really a powerful app with its own set of features, rather a free add-on that addresses a shortcoming in the Attention Grabber.
If you want continuous reminders of Palm events you've missed, Attention Grabber makes for a hassle-free solution.