As I am not as experienced with debian like many others I am going to explain how to set the timezone on debian. It might be useful for one or another too. (Especially if you have "installed" debian with debootstrap)

The package responsible for the timezone is tzdata. I've found the information needed here. The other informations you might find with google are a bit confusing - at least for me. You can (re)configure it with

dpkg-reconfigure tzdata

Just answer the questions and have a lot of fun!