While I have no idea how many games (Classic / PPC) that connect and work fine on the actual Battle.Net services provided by Blizzard, I wanted something where I could connect and play with others without having to assemble a LAN-party or go to one just for the sake of playing a couple of sessions.
The setup appears to be working somewhat, there are still some kinks to work out, like missing versions for the database (you'll know if you try connecting with one that isn't available yet)
So, the easiest way to connect is to add the below information to your system hosts file before trying to connect, these lines will bring you to our server instead of going to the official Blizzard ones.
Modern (OS X, Windows) Hosts File
155.4.9.247 exodus.battle.net
155.4.9.247 europe.battle.net
155.4.9.247 uswest.battle.net
155.4.9.247 useast.battle.net
155.4.9.247 asia.battle.net
Classic (System 7 -> OS 9) Hosts File
exodus.battle.net A 155.4.9.247
europe.battle.net A 155.4.9.247
uswest.battle.net A 155.4.9.247
useast.battle.net A 155.4.9.247
asia.battle.net A 155.4.9.247
World of Warcarft realmlist.wtf
set realmlist 155.4.9.247