I found this leaked beta on a torrent tracker. How do I get it working?
1. Download the game and extract to c:\wolfbeta or c:\program files\wolfenstein or whatever you prefer.
2. Start the game using wolf2MP.exe and create an offline account. You can host your own server now and run around the maps solo.

How about multiplayer?
There are several cracked servers online already, a serverlist can be found here

Can I setup a small server to play clangames?
1. Install Hamachi
2. Create or join a hamachi network. This network will act as a fake LAN so you want all the players to install hamachi and join the same network.
3. One player should start a LAN server. Other players should connect to the hamachi ip of that player. hamachi ip's usually look like this '5.165.199.76' and can be copy pasted from hamachi just like in ventrilo.

Full post and more FAQ can be found here