You might want to take a look at this:
http://save-ee.com/portal.php
100+ ppl were on-line when I "tested" the GOG's version of EE there ;)

Since "Empire Earth and Empire Earth: The Art of Conquest online gameplay system were permanently shut down by Activision " the only way to play those games via internet is through the Lobby or similar VPN creating software.
But don't worry, the Lobby is very user friendly and in addition it has many functionalities that were not present in the native EE client. (Personally I loved the ability to play poker while waiting for mates to join :D )

I have "tested" the whole game on Vista64 and it runs smooth.