IN.power is an R package for estimating the number of susceptibility SNPs and power of future studies.
Save this file in an appropriate folder on your disk.
Park J-H, Wacholder S, Gail M, Peters U, Jacobs K, Chanock S, Chatterjee N. Estimation of effect size distribution from genome-wide association studies and implications for future discoveries. Nature Genetics, 2010, 42, pp.570-575.