This is a list of websites that need mention for one reason or other. Some belong to Friends and others are simply UT based places that are of importance that are still alive. This list will continue to grow as I get time to verify other sites are still up and running,

http://wickedhq.com/
Server IP 76.169.206.194:7777
This is another UT2k4 community site, we go way back as friends in this game. Please pay them a visit. You can find them in the Onslaught Browser listed as:
|ZARK| WickedHQ.com Server.

http://wiki.unrealadmin.org/Main_Page
Best place to start if you plan to start a UT2k4 server either for a lan party or an online adventure.

http://www.3dbuzz.com/
An excellent place to learn how to mod not only UT but many other games.

http://beyondunreal.com/
Another community site that has been around forever, there is a lot of useful information still available there but it will take a bit of poking around in most cases.

http://unrealplayground.com/
A part of the UT community for ever.

https://skincity.beyondunreal.com/
Absolute best place to customize your player character, nevermind unlocking the standard characters this will save you the trouble and give you a lot better options

https://www.epicgames.com/unrealtournament/
This list would not be finished without Unreal Tournament listed in it.