You might try this:

"Our Cleaning Guru Offers This Tip On: Permanent Marker Stain Removal from Leather Upholstery
An effective way to remove the ink stains on leather furniture is by using either hair spray or Armor All. Just spray the stain, then wipe it with a soft cloth. Be sure to test in an inconspicuous area first.

Unfortunately, it is not called "permanent" marker for no reason, and depending on how fresh the stain is, this may not remove the stain completely and you may be stuck with the stain."
from:
http://cleaning.lifetips.com/cs/Clea...moval/Tips.htm