They are all codenames for different versions of Android. Btw, have a look at this http://www.techknots.com/mobiles/all-android-code-names-leaked/
all are codenames of diff Android versions.(Oh Crap,someone has done it already)@Governerd : the url that u r refering to contains many false names.
Version of android froyo,ginger bread ,doughnut,eclairs,cup cake and the latest is honeycomb