You need one phone dedicated as the receiver of your project, or to buy one of these for about 200 euros. http://olimex.com/dev/index.html . Then you can control it with another cell phone. Once you can enough to understand this thread: http://picbasic.co.uk/forum/showthread.php?t=10757 , you probably know enough to build it.

Use the search tool here http://www.picbasic.co.uk/forum/showpost.php?p=26311 and search gsm and sms for some more links.