I know XNA and C# but I am noob(need more exp and more practice) and I want to make some simple games, you guys could recommend me a website or program for game organization?

I want to manage a game whit flowcharts or diagrams every aspect of a game(gameplay, art/desing, marketing, game flow, general concept, technical aspects, ideas, etc...)

I think game organization is very helpfull, usefull, important xD and need to be practiced too, I don't want to have everything in my mind because I can't keep all things/ideas xD.

Please, recommend me an usefull and easy tool for this!.

How about both!

For a website, I would recommend lucidchart. It's very smooth looking and they allow free accounts.

For a stand alone program, I would go with StarUML. Also free, and is a very cool tool once you get used to it. Not as sexy as lucidchart, but no limitations!

Hope this helps!