Remember the Milk is beloved by many people as an application for tracking to-do items and setting reminders. It's been available for use on Android mobile phones for some time, but as JKOnTheRun notes, the application has just had a significant upgrade and supports the new Droid phone. You can run Remember the Milk as a widget on your mobile phone screen, and it works well the high-res screen on the Droid. Check out more here.