Many locksmiths now use TriFlow (teflon) spray instead of graphite for locks and it works better and doesn't leave residue. Also works really well for any metal to metal parts. Just get a can (Ace Hardware has it) and use the straw to spray the inside of your locks.
PB Blaster is a penetrating oil which works well on sticky, tight or partially rusted components. It will do what WD40 does, and then some. It doesn't evaporate like WD40. It can be had at any auto parts store or probably Walmart too.