*EDIT:* This program will make any LAN-capable GOG game work via the internet, without any hassle. Once you have an account, run the client, open the browser, and look for this lobby:
Misc > Gamer-Clans
You can run Tunngle in the background just like steam or xfire, so I'm just going to leave mine connected to that lobby. I hope some GOG'ers are interested in multiplayer!!
*/EDIT*
I think I've found the ultimate app for playing gog's catalogue in multiplayer. It works better than Hamachi in that the max user limit for each VPN is 255, not 10. Also there's really no need to configure each game to "work with" it.
http://www.tunngle.net/en/
The problem is, the folks developing it are German. And they haven't created an english client version.
BUT if you're someone like me who gets more enjoyment out of a game when playing it with others, PLEASE give this a shot...it's worth trying to figure out the german bits (there's not a very wide american audience with this program yet, as it's pretty new) because let me tell you, IT WORKS!
I've tested it with:
Empire Earth
C&C Red Alert 2
Homeworld 2
Counterstrike: Source
Heroes of Might & Magic 3
and all of them just work, without having to mess with config files to make the client work. Has anyone else tried it? Anyone willing to give it a shot? I would die & go to heaven to play against some of you gog-heads.

bump, seriously it's way easier to get people together than in Hamachi.

God yes, Hamachi didn't work for me. DLing as we speak.

Hmm, interesting. Might check it out. But to be honest, it wasn't like Counter Strike: Source's multiplayer feature didn't suck.

Interesting, does it require you to do all the irritating things like port forwarding and what not?

It says you have to sign up for a free beta account, does that mean the final service (I say as if any internet service is ever really out of beta) will be commercial?

This is what I found on the Tuungle website:
http://www.tunngle.net/en/features/
There's a Premium account, so I'm guessing there'll definitely be a paid version when it's released, and a free version.

Yup, seems that way.
Also, tried out HOMM3 just now, IT WORKS. YES. THANK YOU.

Glad someone's finally tried it :) @lowyhong I haven't had to do anything complicated at all... no port forwarding, no config work at all other than installing it. Who knows how long it will be free but I wonder if they'll really charge for it in the future...it really only works as a VPN for gamers, not exactly practical as a business network solution.
@michaelleung Definitely true, there's no need to replace CS:S's multiplayer feature, haha. But it was definitely worth testing with b/c it's a much more recent game, and FPS's are definitely picky when it comes to LAN ping rates. The fact that it runs on Tunngle is noteworthy for some older FPS's that don't have such good matchmaking anymore.

I'm going to write in to them and ask to create a sub-network for DBTS, or even better still, for GOG

Sounds good. bgbrendie you have more experience with Tunngle than I do. Maybe you'd like to edit your first post to let people know which sub-network to join for GOG. We already have Xfire, but I'd much rather use Tunngle since Xfire doesn't support many GOGs.
Btw, you don't need a specific sub-network for a game in order to play the game online with friends via Tunngle right?

Sounds good lh, i'll do that...i hope there is some interest in this, I believe it really is the best solution for GOG's catalogue.
And yeah...It doesn't matter what lobby you're in - whoever's in the lobby with you is connected to your LAN. So you could easily play DBTS in the Company of Heroes lobby if you wanted :) The lobbies just make matchmaking easier.

Ok what we should do is, have everybody put [GOG] on their screen names to identify one another, then we join the "Game clans" lobby. What do you all think?

Sounds good to me, I just hope some more people get interested! :)