Sorry that i do not know where should i post this thread. My research skill is bad and i am lack of time, i wish someone can tell where can i find reliable and latest source of information about the game industry. Now the most important information i need is: 1) The statistics which compare different catogeries of players ( casual, hard-core, female, male, yound adult,... ) in past few years. Hopefully is 2000~2007. 2) The trend of online game nowadays

Generally, information like that is not readily available for free. You will typically have to pay money to a market research company to get such information. I don't know anything more specific than that.

You could always try IGN or gamasutra to see if they have any rough studies available.

-me

(1) http://www.gamasutra.com/
(2) http://www.igda.org/