If you're the one in charge of getting the word out about your organization's next event, then you know what a drag it can be. You've got to make dozens of basically identical phone calls, and in many cases read your script to an answering machine that doesn't interact with you anyway. It'd be nice to turn that task over to somebody else, and use your talents elsewhere. Phonevite might be what you're looking for.
Phonevite is a free service that lets you automate these types of calls. Whether you're scheduling a meeting, reminding folks of appointments, or any other time you need to get in touch with a bunch of people, you can let this service do the heavy lifting.
Once you've signed up for a free account, all you need to do is record your message, enter your list of phone numbers, and schedule a time to make your calls. You can even ask for RSVPs so you'll have a count of who's going to attend, or have them leave a message for you while they're still on the line. You can notify up to 25 people at once, so everybody will know what's going on.