I found a windows installation package at
http://download.gna.org/pokersource/...ws/windows/xp/
Download and run poker-eval.exe, and you will find pokenum.exe in C:\Program\poker-eval\examples. Now add that to your Windows Path variable and you'll be able to run it as a command line utility both from a Cygwin window and a cmd window...
C:\Documents and Settings\Fredrik>pokenum Ad Ah - 6s 7s -- 5s 4s Kc
Holdem Hi: 990 enumerated boards containing 5s 4s Kc
cards win %win lose %lose tie %tie EV
Ad Ah 433 43.74 557 56.26 0 0.00 0.437
7s 6s 557 56.26 433 43.74 0 0.00 0.563