I think the idea is to find the number of different possible 5 card hands now that you have removed 4 cards. In stat we called this "n choose r" where
C(n,r) = n! / ( r! * (n-r)! )
n = 52-4
r = 5
48 choose 5 = 48! / (5! * 43!) = (48*47*46*45*44) / (5*4*3*2) = 1712304
Out of those hands, you must sort the ones that win for each particular hand which gives you the percentage for each hand when you divide # of wins / total possible hands.
There may be an easier way to do it, but this would produce an answer, of course you need a computer to sort through the winning hands as humans would necessarily make an error and miss which pots split etc.
For more than 2 players you have to remember to subtract the appropriate amount for n to be correct. Sounds like quite a programming project, good luck.
Minnejohnny | 
odds of a hand winning? 
