Question: I like to become game developer.. I already work as web developer for the past year. There I used php, jQuery, mysql and some framework also. It's little boring now same thing again and again. So I start to learn Android application development.

My question is:

1. If want to become a game developer  

what skills should I have (like
java, c++, etc) ?
2. Where can I get good tutorials (online)?
3. Is previous knowledge will help me?

Answer: 
To answer your questions, with an Android flavor:

1. Knowledge of C++ will not hurt you, my theory is the more languages you know, the better, period. To develop for Android specifically, Java is important, since even with the NDK, you must use some Java.
2. This really is dependent on what you're looking for, specifically for Android, the article [here](http://www.rbgrn.net/content/54-getting-started-android-game-development), has a lot of good getting started information.
3. Yes, good games will incorporate all kinds of knowledge. Strong math (trig,linera algebra, etc) is helpful. Your mysql experience will be useful for persiting game state to database, though Android uses [SQLite](http://developer.android.com/reference/android/database/sqlite/package-summary.html).

All that said though, there are several similar type questions on this site, which are geared toward starting game development, which you should check out:

1. <https://gamedev.stackexchange.com/questions/4011/getting-started-questions>
2. <https://gamedev.stackexchange.com/questions/41/what-are-some-good-resources-for-getting-a-beginner-started-in-developing-games>
3. [How do I get started making Android games?](https://gamedev.stackexchange.com/questions/3401/how-do-i-get-started-making-android-games)
4. [What things should an indie game developer never do?](https://gamedev.stackexchange.com/questions/765/what-things-should-an-indie-game-developer-never-do)
5. [What are good games to "earn your wings" with?](https://gamedev.stackexchange.com/questions/854/what-are-good-games-to-earn-your-wings-with)
Tank sleep. If you thought 60 hour workweeks were bad before, they'll be distant memories of the easy times pretty soon.

Also, define "game developer". The majority of any programming job is grunt work, programming the bread and butter stuff.
The job "game developer" might appear glamorous to you from a distance, but it's just another programming job (you sound like a junior programmer).
The only difference is that you're programming what happens to a sprite moving across a screen rather than an algorithm to calculate some business data.