Online Tetris - How?

Hy there. This is my first post, and like the most, i have a question ^^
(sorry for my english -.-)

I want to make a (online) Tetris Game for 2,

but how?
what do I need for a online java game, and how can I make it?

I dont want help like “tell me all things or progg it for me”,
just a tip, a book, a totourial or things like this.

Thanks for you reply and best regards

This any help? http://www.ibm.com/developerworks/java/library/j-tetris/