Best place to get tickets?

I'm going for the first time this year...second week of the tournament.

What is the best way to get tickets?

Thanks.

On the official website, it's written that you can buy tickets at the stadium or through tickmaster.

http://www.usopen.org/news/fullstory.sps?iType=12162&iNewsid=298286

I have a question : are there tickets available just before, or even during the tournament, or there are all sold before ?

I'm going tuesday of the second week to the outside courts. These tickets aren't for sale anywhere so i'm taking i buy them at the USTA centre?