What is a good workout plan for someone who has never done it before?

Start slow: The key to starting a work out is to start slow and build, most people try and do too much too quickly and get sore or injured. Start with 10 minutes of walking at a brisk pace and build from there adding 3-5 minutes every 2-3 work outs. When you can walk comfortably for 30-45 minutes then try jogging, eliptical, or stair climbing or adding hand weights but cut your time by half and then build up.