AbbyMe is a free service that makes phone calls for you. While you could use this service to send yourself a wake-up call, or other reminder, its power is in its ability to place calls to several numbers at once. When you send an email to a group, you just list all your recipients in the "to" field, type your message, and send it; when you have to phone those same people, you have to call each of them one at a time. With AbbyMe, you can call a group all at once, saving tons of time for you.
To send a phone message, you just enter the phone number of your intended recipient (or recipients), type in your message, and go. You can embellish your calls by adding media files to them, choosing from a long list of canned sound clips, or you can even upload your own files. Send your message, or use their built-in scheduler to pick a future time to send your message.