Source: http://technotes.twosmallcoins.com/?p=279
Putty is a good SSH client for Windows.
1) SSH into your remote OS X machine with an administrator’s log in and password.
2) Enable Remote Desktop (a.k.a. Screen Sharing, a.k.a. VNC) with this command:
sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/kickstart -activate -configure -access -on -clientopts -setvnclegacy -vnclegacy yes -clientopts -setvncpw -vncpw mypasswd -restart -agent -privs -all
3) Login using a VNC client. As I mentioned, TightVNC worked for me; for some reason, RealVNC and UltraVNC didn’t. Your password is “mypasswd” (see the -vncpw flag in the above command; you can and should change this).
