How do I change the time zone on a Canon 50D?

I just connected my EOS Rebel XTi to the computer and used the Canon software (EOS Utility) to sync the camera time with the computer. However looking at the Exif data from the raw files from the camera there is no notation of the time zone. It could possibly be part of the OS, or as you said it could be a function of Flickr or something else.