I don't know if anyone's been keeping up on this, but a new company (SpareOne) has a cheap cell phone available to the general public. It doesn't have a screen and can only do basic cell phone things, and it doesn't require charging...all you need is a AA battery (included) for emergency calls. You can also stick a SIM card in if you want to use it like a regular phone. They have two models: one for the US, and one for international use. Oh, and if you store it properly, the battery has a fifteen year shelf life.
More info can be found here, and they've got a deal going on for $10 off one phone until May 8 if you use the coupon code SOPLAY05.
This isn't a paid ad, but I like the idea of having a phone around for emergencies. I picked one up a month or two ago to keep in the car.