You know how some hotels will give you a wakeup call if you’re worried that you won’t wake-up in time? Well, you can get the same kind of service using a site such as Wakerupper or WakeupDialer. Both services will call you at an exact time you specify, but each have their own benefits. And both don’t even require an account for you to start using them.
WakeupDialer is convenient because it is fast and completely free. Just enter in your phone number and the time you want a call to come in the next day (you can’t schedule a call for the same day). It even appears to automatically select your timezone, but you can confirm that it will be calling you at the correct time by looking at the “Click here to call …” button which tells you the amount of time it will be before your call will come in.
Wakerupper is nice because you can specify the message you want played back when the call comes through. You can also schedule calls for the same day which is convenient for using this as a reminder service rather than just for a wake-up call. The downside is that the service only appears to be free for the first 10 calls to your phone, which means frequent users will have to sign up for a plan to continue using it.
So you can use the service that sounds right for you, but remember that both of these only work in the US and Canada.