Interrupt Me! for

From Remy Sharp:

Interrupt Me! is a simple to use, small app that allows you to set up multiple profiles of alarms with different associated alarm sounds. When you're spending your lunch reading the latest e-book you've downloaded on to your palm, you might over run, so Interrupt Me! will pop up and tell you to get your ass back to work - or what ever you want to use it for :)

Interrupt Me! is also perfect for setting alert tones for taking medicine, using the phone alert to remember to make a phone call and bird chirps for meetings.