AlbinoBlackSheep.com – Hosts lots of games and videos, features tutorials on working with Flash.
FlashKit.com – Numerous tutorials for working with Flash including step-by-step guides for certain types of games.
Kirupa.com – Extensive collection of tutorials for Flash including guides for specific types of games such as shooters.
Lassie Adventure Studio – A 2d creation image with the feel of the old style Lucasarts games.
Sploder.com – Create a Flash game from a wide range of objects and then embed it into your MySpace, Blogger, and more sites.
General Sites & Resources
Anim8or.com – A 3d modeling animation system.
byond.com – Create your own games with their tools, host them on the site, let thousands of people play.
GameDiscovery.com – Everything you need to create a game including a pool of ideas submitted by users.
Martin Piecyk’s Website – A guide to learning how to make games with links to numerous resources.
VGMusic.com – A gigantic archive of video game midi files that, after asking permission from the people who made the files, you could possibly use in your own freeware games.
Visionaire2d.net – An engine to make 2d adventure games with no programming language knowledge required.
YoYoGames.com – Provides game making tools, beta testing, downloads, works in progress, a community and more.
Charas-Project.net – A character generator for use with RPG Maker.
CrankEye.com – Lots of resources for RPG Maker including character editors, soundfiles and more.
DualSolace.com – Home of the RealFeel 2D MMORPG making software.
FreeMMORPGMaker.com – Home of the Eclipse MMORPG software and also includes many resources for your games such as sprites and sounds.
PhanxGames.com – RPG making resources such as graphics, midis, and wave files. Able to upload games up to 50mb in size.
PlayerWorlds.com – A popular system for crating MMORPGs.
RPG Maker – Home of the series of the RPG Maker series of programs.
RPGCrisis.net – Downloads and tools for various RPG engines.
RPGRevolution.com – Tools and utilities for 13 different game making engines.