bballmom - I like the idea of being able to talk to someone thru the pendant. I looked at your link, and the only concern I have is battery life. Make sure you keep an eye on the battery!
I got a pendant for my dad last year from Phillips Lifeline:
http://http://www.lifelinesys.com/content/home. I got him the one with auto-alert. The pendant has some type of gyroscope inside, so if he falls and can't push the button (if he hits his head or something), it will recognize the fall and will automatically call for help. They'll come over the speaker and if they don't get a response, they'll automatically send the ambulance. The pendant is waterproof, too, so he can wear it in the bath/shower. (
IF he doesn't take it off; my dad takes his off, and since he fell in the bath last year, it won't do him much good if he's not wearing it!)
Installation was easy, and they have you go to different parts of the house to test the range. He has a small house, but every part of his house was within range.
I don't know if the cost varies depending on what part of the country you're in, but here in PA, it costs $50 per month.