Online Game Sites

New

Buy Games @ AMAZON.COM My new store to purchase games from Amazon.
Netzero Games Just found this one and have not had a chance to check it out yet.  Upon initial inspection it compares to Pogo or I Win
Omgpop When it comes to playing games and meeting new people online this could be the next great social website. This site is a clear example of that. In case you want to play free multiplayer games and meet other people at the same time, stop by and you will discover a good range of options to choose from.

Long established

Gamesville - Lycos games free site.
MethodShop One of my favorite sites, not only does it have games but funny pictures and other entertainment.
4kids - New find for me, have not checked it out well yet
Pogo - tons of games and you can win prizes too!
I Win - tons of games and cash prizes available
I Won
MSN Games - Tons of game, requires a small download to play certain games
Heavy Games – TONS of free web games!
Free Game Heaven - Play the best free games online!
ArcadeTown.com - Tons of free online games plus video games
Arcade Nut - FREE flash and java games to play online. FUN for all ages!
Smashing Games -A good source for free flash games, added daily!
Free Online Game List- This directory lists dozens of high quality free multiplayer online games, and includes a description and screenshot of each.
Online Game Library - A great selection of online games of all types, although not all are free.
Arghhh.net - Many  Java and Shockwave games by a small design team.
Yo Games- Directory of games
Noodan Free Games-  Hundreds of free games to download and play
Martial Combat- Fantasy Martial Arts game set somewhere between the classic martial arts movies and the world as we know it today. There aren't any special power blasts or superhuman strength, just good, old fashioned nonstop fist in your face action. 
Computer Games Online -A very comprehensive and useful guide to games. Frequently updated.
Cybertrek - The world’s first adventure game that requires you to know how to use your computer! You could win $500 ... if you make it all the way through the seven episodes.
Gameworldx- Exciting listing of hundreds of games