I have no wall switch for my ceiling fan lights or the fan itself. I wish to find a 3 position pull chain light switch so I can have OFF, FULL AND DIM for the lights. For DIM I would put a IN 4003 diode in series with that position wire. - That would give me 1/2 dimming. My problem is: I can't find a 3 position pull chain switch. Can someone help?

Any hardware store should have that switch, it is a 2 speed (SPDT) pullchain.

You can also buy inline light dimmers, as would be used in a halogen pole lamp.

http://www.ceiling-fans-n-more.com/ceiling-fan-pullchain-replacement-and-repair.php