Another free online Pokemon game is called Pokemon Omega - play it whenever you want, just sign up for an account. Once you have an account, you just login to site whenever you feel like playing a game. You start the game, like most of these types of free Pokemon games, by choosing a starter Pokemon and then go exploring the worlds hoping to catch more.
This game is that much different to other online games like Pokemon Crater, the layout and game play is pretty good and it's web based so no download is needed. The site layout is fairly good giving you easy access to all areas you want to use. And the trading system has been well thought of and works just as I like.
They say they are using official Pokemon game data, well maybe but don't think it is any way an official game by Nintendo. Pokemon Omega matches up not just the Pokemon types but also Stats to make the battles even better. This means that if you really are into Pokemon online games, and who isn't :), leveling up, battling and overall gameplay is not just a quicktime thing but a full on game.
They also say they have used Ajax style programming to make the game faster and it does seem so. It acts a lot faster than a lot of other games I have played - I don't have to wait for the screen to refresh every time I take a step in the map areas - a real pain on other games.
The game designer seem to have a good ranking system in place. Although I couldn't really tell, they say it is based on Trainer Points that you get by winning battles, completing certain achievement and things like that. The battles themselves will have a bit of animation, nothing like the battle animation in Wii Pokemon Battle - don't expect that, and the world map acts a little like world maps in real games - not bad at all. At the moment the game is in early Beta but still not a bad effort, not many people seem to be online, maybe that will change!
Also check out exciting the Free Monster Games and interesting free online RPG games blogs I write. Keep checking back here for more of the Online Pokemon Games.