Hi Beverly!
I started jumping rope for cardio about a year ago. The reasons I started roping were because I needed a form of cardio that was convenient when I couldn't do a tape and because a friend (a sister pear shape) suggested that it would help slim down my butt and thighs (she was right!). If I'd been more consistent with my roping I would be able to rope for 30 min. at a stretch now, but I'm only up to 2 sets of 15 or one set of 20 minutes.
Roping definitely works almost the entire body, in my opinion - you'll feel it in your arms, abs and legs if you're doing it correctly. I ordered the "Jumping Towards Fitness" Kit from
www.exude.com (Edward Jackowski) and an instructional tape was included. (I don't particularly agree with some of his exercise theories, one of them being that "spoon" shapes shouldn't do weight bearing exercise for the lower body at all - whatever. It's done wonders for me, but I digress). The tape, despite it's poor production quality, is a great one for instruction and tips on form, etc. I've heard that
www.ijumprope.com also has a great instructional tape. It's important to rope correctly to avoid injury (i.e. shinsplints) and to get the most benefit out of your workout.
I guess I just gave you a lot more info than you were probably looking for

Sorry for being so long-winded. But I rope 3-4 times a week and it's just such a great workout. . .
Hope this helps.
Randi