usually :
a. master keys will unlock all locks including glove box
b. valet keys will start the vehicle but will not unlock the glove box
c. sub keys will only unlock the doors
transponder keys have a black covering over them usually and be slightly bigger than the old style master keys (pre transponder keys)
on the new 03-04 keys, you have 2 master chipped keys (black fob), and a valet chipped key (grey fob). i had a sub key made to just un/lock the doors so i can run the truck during the sub zero winters and leave the master chipped key in the ignition.
my wife has the other master chipped key (black fob) and i keep the valet chipped key (grey fob) in the safe, in case i lose a master key. since you need either the master/valet chipped key to program another chipped key.
as far as cutting a new key, they can usually look up the master key id and cut a new one, unless you have the master key id plate.
as far as programming a new chipped key, i am not sure how they work prior to the 03 models, since you are able to drive the vehicle off the lot w/o a chipped key. the 03 and newer versions, the engine will not stay running w/o a chipped key.