You are correct that you should not strength train the same muscle groups on back to back days...the body makes the adaptation to your strength training when you are not working out. Some studies even go so far as recommending a soild 72 hour rest.
If you have not visited SparkPeople's Fitness Resource Center, below is a link to do just that. Lots of great articles and information to guide you through the process. www.sparkpeople.com/resource/fitness.asp
I hope this helps!