The latest version of Qtracker (http://www.qtracker.com
) lets you launch a server with QT Uplink and let other Qtracker users see your server, from a master list.
Of course previous versions of Qtracker had JK/MotS support, but once the JK.net IP board went down permanently in 2001 it was effectively "broken" (LAN only) until recently.
You can also of course hook up games with people on GameSpy Arcade (you can find people with the game installed and set one up in their rooms for example).
The MSN Gaming Zone I'm not sure about. I heard they were removing support, but then I heard they were just taking it off the main page advert, so it might still be supported there. Kali I'm not sure about, but it was a pay service so I never bothered to join.
Many old "dead games" still have ways to play them online, so it's difficult, but not impossible.
Interesting about the "dedicated server," I'll have to check that one out!