Hi Mick,
I have just been through a similar exercise and, after a quick lesson (thanks Ken!), think I have fixed up my door hinges good as new. Its unlikely that the steel pins have worn much, more likely the (brass?) bushes. Good pins and relatively unworn bushes can be obtined from rear door hinges of wrecked cars but I found some remanufactured bushes at Scotts Old Auto Rubber in Melbourne (phone 03 9563 3023). These have to be ordered in but only cost $3 each and seem to work real well - cat number is 376.007. I think American Autos may also sell them?
All you have to do is knock the old pin and bushes out with a punch, fit new bushes, load up with grease, and hammer in a pin. Mine are a bit stiff at the moment but I think they just need a bit of use and my car is current in a million bits...ho, hum.
Jonno