Robin, when you start with weights (outstanding idea, BTW!) you will want to do exercises for ALL your muscle groups. Otherwise you're going to strengthen some muscles and not the opposing muscles, which results in muscle imbalance and injury. So you want to target your back, chest, shoulders, abs, legs (quads, hamstrings, and calves), biceps, and triceps.
A good place to start is with full-body workouts three times a week (like M, W, and F). Pick an exercise for each muscle group and pick a weight that lets you do 12 - 15 reps. If you can only do 8 reps, the weight you picked is too heavy and you need to lighten up. But if you get to 15 reps and can keep going, you need to raise the weight next set. If somewhere between 12 and 15 reps, it becomes hard (or impossible) to do another rep, you know that's the right weight for you.
Do two sets of each exercise. Start with your large muscle groups and work to the small ones: legs, back, chest, shoulders, bi's, tri's and abs.
Check out the stickys in the LWL forum for ideas about what exercises to do.
Exrx.net is also a great resource and has some workouts for beginners. And you'll have hours of fun checking out
Stumptuous.com.
