EDIT: dopey me... I asked because I was using the imagex tool but it wasn't working. Here is the code:
CODE
imagex /info e:\images\a410xp.wim 1 "XP Home Drive C"
imagex /info e:\images\a410xp.wim 2 "ETC XP Pro Drive C"
imagex /info e:\images\a410xp.wim 2 "ETC XP Pro Drive C"
where 1 or 2 is the image index number, and the part in quotes is the new name.
You can check that you updated properly by not having any args after the image name.