ReRemind is a simple Windows Mobile service that will play a sound at a specified interval when an event is waiting your attention. This is particularly useful for devices that lack standard amber/green notification LEDs (like the Diamond / Touch Pro), but can be used with any WM device if you want audible notifications.

Changes:

V4 – BETA – Fixed SMS/Email notification bugs. Deletes stale notification queue entries on startup/exit for if device crashes. Added 10 second delay to start service on boot.

http://forum.xda-developers.com/showthread.php?t=498161