GOB.. start the C25K program. It is a program to get you from the couch to a 5k run in 9 weeks. It starts you slow with a short run & longer walk. It progressivily gets longer runs with shorter walks until you get to a full 5k run.. I did the program this past year. I hurt myself with my first 5k race, and am getting back to running again. here is a link on the program.
http://www.coolrunning.com/engine/2/2_3/181.shtml
Feel free to ask me any questions..
Oh make sure to get proper shoes that fit you & work the way you run, makes a big difference.