WordNet (r) 3.0 (2006):

errand boy
    n 1: a boy who earns money by running errands [syn: messenger
         boy, errand boy]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "errand boy":
   Ganymede, Hebe, airline hostess, airline stewardess, attendant,
   batman, bellboy, bellhop, bellman, bootblack, boots, cabin boy,
   caddie, callboy, caller, chore boy, copyboy, cupbearer,
   errand girl, footboy, gofer, hostess, office boy, office girl,
   orderly, page, squire, steward, stewardess, tender, trainbearer,
   usher, yeoman