Amber, here are three links to get you started. I'm afraid you've a bit of reading to do, since "healthy" has become such a subjective term depending upon what one's real goals are, and I would rather hand you some unbiased information so that you may decide for yourself.
The first two links are from the American Medical Association and are .pdf files of booklets aimed, in very general nature, toward physicians in private practice. There are some really good formulas and charts there, as well as a ton of insight for the patient. The second link is more specifically the height/weight/body mass index chart I think you are seeking.
The third link is to the American Heart Association's "Healthy Lifestyle" section, that is the beginning of a huge wealth of information on layman's terms.
I hope that helps to get you started!