This is entirely written off the cuff, so to speak.
After about a week or so of reading many forums and such, I've basically come to a conclusion that the people of the Doom3World.org community are a step above the rest. This is not to say that all the other places of interest suck exactly but they don't carry the same moto, "Knowledge is key." Hopefully, there will be some interest in the doom3world community to see a thriving HL2 editing community as well.
The following is a list of tools, resources, tutorials and other forums related to HL2 and CSS.
First thing should be how to properly setup Hammer to edit CSS. If you would like to take it upon yourself to edit HL2 that's great but I do not belive there is a HL2 fgd as of yet. This will come soon enough in the full sdk... well with valve that could be a year
Feel free to add below your own resources and I will add them to the list.
Nems Tools http://countermap.counter-strike.net/Nemesis
This is the home of several tools but most notably to me is GCFScape and BSPViewer. GCFScape is an explorer that will allow you to extract the contents of the game, works with HL-HL2 CS CSS etc. So if there was something that caught your eye in HL2 and wanted to know how it was done etc. use this to extract it.
*Note You must exit steam before opening the gcf files with GCFScape as they are in use by steam.
gcf = pak basically.
ZHLT Compile GUI X² http://www.planethalflife.com/eddi/
Compile tools from old school HL, ZHLT mentioned in his last .plan that he intended on further development to support hl2 and CSS so stay tuned.
Forums and Tutorial Sites
HL2 World http://www.hl2world.com/wiki/
The Snark Pit http://www.snarkpit.com/
Steam http://www.steampowered.com/forums/foru ... forumid=41
Hammer Editor Manual
General Sites of Interest
*Note: Information on getting hammer to compile, copy bsp and run CSS after the compile procedure.
http://www.chatbear.com/board.plm?a=vie ... &v=flatold
*For getting HL2 to work with Hammer awaiting the release of the full sdk go here. http://halflife2.filefront.com/news/;13936
Included is an HL2.fgd
Side note I finally got the textures for HL2 to show up by extracting the game contents to Steam\SteamApps\youraccount\sourcesdk\hl2.