Javascript (311)

This assumes there is a function called print, to output a string.

n=100;while(--n)if(n>1)print(n+" bottles of beer on the wall, "+n+" bottles of beer.\nTake one down and pass it around, "+(n-1)+' bottle'+(n-1>1?'s':'')+' of beer on the wall.\n\n');else print("1 bottle of beer on the wall, 1 bottle of beer.\nGo to the store and buy some more, 99 bottles of beer on the wall.")