Which Server/Protocol should I use to create real time interactive online game in Flash?

I'm totally noob in flash development and I"m now looking into multiplayer online game in Flash. What I found out are...

**Commercial One-stop Servers**
Electro Server (http://www.electro-server.com/)
Pulse (http://www.gamantra.com/pulse/)

**Free**
Openfire (XM开发者_开发知识库PP Server) and Red5 Plugin
Hemlock (http://hemlock-kills.com/)

I excluted amfphp because it is not designed for multiplayer gaming if I'm not mistaken.

So my questions is what should I choose to start my game? Please share your knowledge and I'm really appreciate your help!

The two most popular servers right now (April 2011) are: ElectoTank - http://www.electrotank.com/eup.html SmartFox - http://www.smartfoxserver.com/

I have personally used ElectroTank a I really liked it. If your project is of limited scope with no commercial ambitions, the choice is up to you. But if you are a small group or single develper, the support and documentation provided by the commercial products may be worth the cost to you.

Also there are a few websites with their own multiplayer API's that you can use. This might be the very best approach for a "noob" to flash game development. For example: nonoba - http://www.nonoba.com/developers/multiplayerapi/overview whirled - http://www.whirled.com/

In this case you don't even need to set up a server, and there are no costs associated with using their APIs.