Unluckily for GOG I already had my own original copy of 7K, I hope that thanks to GOG the game get a big enough community for some decent multiplayer,

here's my little contribution to make it easy for customers of GOG to setup a multiplayer game with friends:

Connecting 2 PCs for Wi-fi game

- Wifi required on the PC (all laptops already have wiki)
- Create "ad hoc" wifi network, (WEP protection is fine, and a 5 letters password, i was trying to connect win Vista and win XP and found that win XP had some problems with WPA)
- Then connect all PCs that you want to play with. (in my case I used "name: 7King and pw:12345" but I suggest you to use some better password (WEP connection is not secure anyway)

I used Vista as server and XP as client,

Once all PCs are connected start 7k,
multiplayer-> TCP/IP ->Create

-When you are in options window you can start connect all ohter PCs
multiplayer-> TCP/IP ->Join (leave blank and press Enter for autosearch a game)

It's done, enjoy!

(multiplayer games can be saved and resumed, when someone save the game the same file is written for all players)

Note: I don't know how's working for GOG, but my version requires original CD for up to 4 players, I don't know if GOG version still require the CD or not.