Body Surface Area
Formula :	BSA (m2) =
Mosteller :	= √ height (cm) x weight (kg) 3600
DuBois & DuBois :	= 0.20247 x height (m)0.725 x weight (kg)0.425
Haycock :	= 0.024265 x height (cm)0.3964 x weight (kg)0.5378
Gehan & George :	= 0.0235 x height (cm)0.42246 x weight (kg)0.51456
Boyd :	= 0.0003207 x height (cm)0.3 x weight (grams)0.7285 - (0.0188 x log(weight))

Lean Body Weight (men) = (1.10 x Weight(kg)) - 128 ( Weight2/(100 x Height(m))2)
Lean Body Weight (women) = (1.07 x Weight(kg)) - 148 ( Weight2/(100 x Height(m))2)

Ideal Body Weight (men) = 50 + 2.3 ( Height(in) - 60 )
Ideal Body Weight (women) = 45.5 + 2.3 ( Height(in) - 60 )

Body Mass Index = Weight(kg) / Height(m)2

The Federal guidelines on the identification, evaluation, and treatment of overweight and obesity in adults released by the National Heart, Lung, and Blood Institute (NHLBI), in cooperation with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) defined "overweight" as a body mass index value between 25 and 29.9; and "obesity" as a body mass index value greater than or equal to 30.

References:

Mosteller RD. Simplified Calculation of Body Surface Area. N Engl J Med. 1987 Oct 22;317(17):1098. (letter)
DuBois D, DuBois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Int Med 1916 17:863-71.
Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: A height weight formula validated in infants, children and adults. The Journal of Pediatrics 1978 (93):1:62-66.
Gehan EA, George SL. Estimation of human body surface area from height and weight. Cancer Chemother Rep 1970 54:225-35.
Boyd E. The growth of the surface area of the human body. Minneapolis: University of Minnesota Press, 1935. (From: http://www.ispub.com/journals/IJA/Vol2N2/bsa.htm)