Here are a few Quake 2 links!

Mining Co. - Here is one of my personal favorites because it has all you need to get started online with Quake 2 and is really well setup!

Planet Quake - This is a really well known Quake 2 webpage and has a lot of really detailed shit!  Lots of help for programming  and other complicated stuff.

Player & Server Search - Just as it sounds.  Ever wonder if one of your friends is online?  Just type in there name and the rest is done for you!  The server search allows you to view servers in a certain area, certain mod, or certain map!  Nice place!

Qoole - Here is an awesome level editor that is very nice and lets you try it for free.  If you order it you get more textures and options.  If anyone has a place where I can get the full Qoole v2.50 install, please let me know.