http://dtdb.co/ The beginning and end of all your deck building needs. Browse other peoples decks, browse cards, and build your own.
http://pineboxentertainment.com/resources/ The official sight and the updated rules of DTR.
https://discord.gg/w4uknb3 Join the chat board. Find friends, opponents to play online, discuss deck ideas, simple rules questions, and DTR news. It's where many of the people most passionate about DTR hang out.
http://www.octgn.net/ A really great way to play the game online. Takes a bit of set up, but the people online are great, and very helpful. Stop in on discord and we would love to help.
Game concepts explained.
https://www.youtube.com/watch?v=qXH_P79PDlM deck building basics video
http://forums.pineboxentertainment.com/t/updated-buyers-guide-to-doomtown-reloaded-introductory-decks-for-2x-base-set-plus-expansion-decks/2035 An excelent article of introductury decks that go 1 step beyond the prebuilt decks in box.
Fan based websites.
http://forums.pineboxentertainment.com/u/system/activity/topics This is a list of topics are articles put out by Gomorrah Gazette. There are some great reads from the doomtown past.
http://analoggaming.libsyn.com/ Booted dudes have a fun podcast where they discuss what is current in doomtown.
http://rndranch.weebly.com/ I really respect the card analaysis on this sight.
http://the-gadgetorium.blogspot.com/ Not currently being updated, but there is some really great work on this website to read. Note that many of the collected rulings are correct, there have been some changes, and the old forums that the list refrences is dead.
https://www.youtube.com/watch?v=pLkbV6jtzcA&list=PLolCl5TCZC0aGlD6IbMT6diHr8AT3I8zy Some good game play videos so you can see what experienced hucksters do.
https://www.youtube.com/user/AdmiralGT Some tournament videos, high quality editing, worth watching if your studying the game.
If you have any websites you love that I missed, please either reply here or message me, I'll try to keep this list updated.