Estimating genetic differentiation ( Fst ) for four populations?

Question

Fst = (Ht-Hs)/Ht
Where Ht is the expected heterozygosity of the total population
andHs is the average expected heterozygosity from within each population

If there are two populations
Then
pop 1 :p=0.76,q=0.24
pop 2 :p=0.80,q=0.20
therefore
2pq=2 x 0.76 x 0.24 = 0.3648 in pop 1
and
2pq=2 x 0.80 x 0.20 = 0.32 in pop 2
This means that
Hs = (0.3648+ 0.32)/2= 0.3424

To calculate Ht
average p = (0.76+0.80)/2 =0.78
average q =(0.24+0.20)/2=0.22
therefore
Ht=2 x 0.78 x 0.22 = 0.3432

From these two values we can say

Fst=(Ht-Hs)/Ht = (0.3432-0.324)/0.3432=0.002331

BUT WHAT if there are four populations
Please help to explain

Answer 1

http://rds.yahoo.com/_ylt=A0geu900uLZGtWUBYaBXNyoA;_ylu=X3oDMTE5M2YxM3YwBHNlYwNzcgRwb3MDMQRjb2xvA2FjMgR2dGlkA0Y4MjJfMTExBGwDV1Mx/SIG=127uiimgk/EXP=1186466228/**http%3a//www.genetics.org/cgi/content/full/163/4/1467