This is great as you put in your pre pregnancy weight and height so it can calculate your BMI etc and tell you what is 'normal' to put on for your current needs. Obvisouly a rough guide but better than most graphs and things as it's customised to your weight and height and everyone is very obviously very different.
http://www.indiacurry.com/women/pregcalc.htm
http://www.indiacurry.com/women/pregcalc.htm