Focus on being healthy, eating healthy and having an active lifestyle, and your body will balance out to its ideal weight. You could be anywhere from 130 to 210 and still be healthy - remember that muscle weighs more than fat.
Some of these answers are good quester2011 is right diet is a big part of it and you want muscle not fat. Shylilac has some good links check them out as well. They are very use full I use one them every month.