You need to download the 1.04 patch for best MP results. Download it here (
http://jediknight2.filefront.com/file/Jedi_Knight_2_Patch_104;3825) and follow the installation instructions.
Next you fire up the Multiplayer game from the start up menu, and select "join server" from the play menu. Make sure you set the source option to "Internet," otherwise you won't get any servers listed. You may also need to refresh the server list from time to time. Simply select the server you want and join.
Before you start, I should warn you that the Jedi Outcast (and Jedi Academy) online community is a wierd bird indeed. There are two major "camps" who play JO:
#1-The Honorz Horde:
These guys are unfortunately the dominant force in the community (at least, they were the last time I checked). These people abide by a set of fabricated "honor" codes, such as only using lightsabers and only defeating foes in duels. They claim these codes encourage good sportsmanship and valor.
Do not be deceived. By making the game so restrictive, they rob JO of its fun factor. They abide by the "honor" codes with an almost religious zeal that rivals any real world fundamentalist extremists. What's worse, they've created a plethora of abusive modifications for their servers that punish any heretic that has the audacity to play the game like the developers wanted us to play it. Offending players are publicly humiliated, ridiculed, ostracized, hunted down and finally banned. Being on the recieving end of such a "server jihad" is unpleasant to say the least.
In short: stay away from these people by any means necessary.
#2-Regular Gamers:
This is the category I fall under. Regular Gamers play the game like it's supposed to be played, with all weapons and Force powers and a competitve style of playing. You'll have a blast with these guys, trust me.
Unfortunately, there are few Regular Gamers left. With the advent of the Honorz Horde, they have succeeded in corrupting many to join their side. They actually will try to hijack other servers to teach their "honor" lies, and they have been disturbingly successful. They now control the majority of servers. A good way to check in on a server is to spectate for a while. Are players just sitting around in a circle watching a duel, talking more than fighting? If so, then get out of there IMMEDIATELY: you've stumbled into the Horde's domain. If there are more kill notifications than chat messages, then sit back and enjoy playing MP with Regular Gamers.
There are good servers out there, such as Amidala's Chop Shop servers. There are a few other safe havens out there, but you usually have to wade through the Horde's servers to get there (unless you actually like how they play). Once you get to a server you like, however, JO can be an incredibly fun multiplayer experience!