See... now you're getting into a whold different realm that goes beyond Jailbreaking. Jailbreaking allows you to modify your themes, icons, colors, ect. Mostly this is done through themes & tweaks found in Cydia. There are resprocities that allow you to download apps and install hacked/pirated items (those of which are not to be discussed on this forum). That in turn does not make the actual Jailbreaking of your phone illegal.