I've was working on a SMS message reader a while ago, but have placed the project on hold.
From what i remember, i used a nokia mobile phone (cell phone) and i bought a nokia data to USB lead, and just used hyper terminal to send commands to he phone.
I chopped the usb connector off and used the raw RS232 lines once i had the commands all figured out.
The phone resonds to AT commands, but you have to get a nokia phone that is xxxx compatable (cant remember the name of the protocol) and not all nokias are. Only the newer (last 1-2 year old) models.
I have sucessfully read the indox, and the entire message. And i have also sent a text message from the phone.
If you want my notes on the commands i sent, i'll try to dig them out.