I didn't have a chance to play the game in multiplayer back when it released, I had dial up connection and only a few hours per week of internet usage back then. But the game seemed like it would be awesome to play multiplayer. Now that it's been re-released on gog, are there any multiplayer games going on?

Yes you should visit giantswd.org and download chatex gcksb where there is a dwindiling communityof which i am apart

This game has multiplayer? I had no idea. Was too busy having fun with the campaign to notice.

There is a "Giants" network on Tunngle. No one is in there. Has anyone tried that? Tunngle is a pretty good way to play games over LAN, similar to Hamachi but with a better way to find networks I think.

Tungele only works with popular games like call of duty or minecraft old games are forgoten there

There is unofficial group on Xfire http://www.xfire.com/communities/gogcom/ where You can play gog games online with others players.