playerio.com — Player.IO is web services for Flash games.Player.IO makes it easy to build scalable games, with services for Multiplayer Games, Storing Game Data and more...

armorgames.com — Another site with lot of great games and a way for your to embed your games in your portals.

freelanceflashgames.com — I found this site and it looks really useful for anyone getting into Flash Game development.

kongregate.com — Top Flash Game Site