I have searched the App Store for the best free countdown apps. Here are my top 3:
1. Doing Time. This is my favorite App. I really enjoy watching the percentage change as the days pass by. The only downside to this app is you can only track one event at a time. UPDATE: After updates, you now can track multiple events. Which makes this app even more useful and fabulous!
2. Countdown. I also like this app for tracking a single event. Different from the "doing time" app, it allows you to see how many months are left in your countdown.
3. Countdown +. I like this app for tracking multiple events at one time. On my list I have a countdown to my college roommates wedding, the Disney princess half marathon weekend (we are doing the 10k though :), and my husband coming home.