There is no other difference apart from the number of legal licenses you get.
With XP Pro, you can legally install it on only one desktop and one laptop. XP Pro requires activation.
With XP Corp, you are given more licenses, which means you can install it on more than one computer. As Zedric said, the smallest volume license allows you to install it on 10 computers. XP Corp does not require activation.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS