Interop with *nix systems in corporate enterprise

Hello experts,

Does anyone know of a working (maintained) solution to enable SSH between *nix and Windows servers? I've seen examples of OpenSSH and/or CygWin (stand-alone) implementations but not one that has any enterprise management framework. I realize that certificates could be a future solution here but the first step, to integrate with the existing ssh key management solution, would help foster that initiative. Any info that you can pass along would be greatly appreciated.