How do you calibrate a 5.1 surround sound home theater?

I am wondering what the best way to calibrate a 5.1 surround sound system. I just purchased at theater in a box 5.1 system. Do you set the levels of the different speakers to a certain loudness? What am I supposed to listen for?

Are there any DVD movies that are available that have a channel test or a good one to test/enjoy excellent surround sound mixing and design?

thanks!