UPDATE: If your having issues you may want to try the free:
One of our readers, Stephanie, sent in the news about this new free application. It is a very simple Countdown timer for BlackBerry that is available for OTA download only. It comes from the good guys over at www.northcubed.com.
Countdown functionality is supposed to come with OS 4.6 but this is a great way to add the functionality for free.
From the description on the product page:
Usage is simple enough, start the application, set a countdown period and select start, you can toggle pause using the spacebar and when the countdown completes there’s an unobtrusive 2.5 second vibrate to let you know you should be wrapping up whatever you’re doing.
Download using your BlackBerry browser: