Remember The Milk
Here is another cool site, called "Remember The Milk". It is basically a place to list tasks, but it will email or phone you at a predesignated time before appointments, you can add tasks to it by email. It can sync with icalendar if you are a Mac user, but it really is worth checking out. To do lists can be added and will automatically update on your Google home page. Between this and Hassle Me, we shouldn't forget another thing!!!