There's really no program/s needed to make the skins. You will need something like Paint Shop Pro or Photoshop for the graphics if you choose to change them.

If you want to make a skin, go into this link and download a zipped file called generic_theme.lwtp. If you never made skins before this may confuse you at first until you play around with it for a bit.

http://www.limewire.com/english/content/makeskins.shtml