You can pick it up here:
http://enemy-territory.4players.de:1041/It's addictively fun. I play at least a few times a week. Playing against other human beings is far more challenging than playing against bots. I can usually give tit for tat and sometimes more depending on how many pain meds are flowing through my system. ;) Hehe.
I picked up the Private Ryan sound pack and another pack that turns the Germans into real Nazis with swastikas and everything. Their uniforms are darker, so if you turn up the brightness, they're easier to hit.
There are several classes: medic, engineer, soldier, field ops, covert ops. As you play, your experience increases and you are rewarded accordingly. Servers that have XP save are at first very challenging. Then when you rack up the XP, you can more easily win against people that have just joined. Other servers reset XP, which is more fair. I enjoy the XP servers because I like to get things like two pistols, faster reload, better accuracy, etc.
If you like multiplayer, try it.