all the answers thus far are good and rooted in scientific inquiry. one simple formula that is quite good for most bodily habitus and has stood the test of time(few centuries):
100 pounds for first five feet
plus five pound for each additional inch. e.g.
ideal weight for 5' 6" person would be 100 +30(6x5)= 130 lb
folks with thin arms and legs(+/-) beer belly(mesomorphic) may need to shave off 5 lbs whereas large boned or muscular folks can add 5 to 10 lbs.
hope this is of some value to you.