Dude, as the post before me said, clean up the areas where its dripping from. Once degreased and dry, be vigilante on looking for the leak. Get under there after every trip. Catch it before it has gotten low enough to "spread" out. If your undercovers, are on take them off and leave them off. As Tim said, look for the highest place above the wet spot. I like to use brake cleaner as it leaves a very dry "haze" which makes leaks easy to spot.
In the post i quoted, you said your PS fluid is "now" low. Did you mean to say "not" low?
Also, the amount that is leaking might not show up as causing problems for a while so you can't diagnose leaks like that. If' it's coolant, you certainly don't want to wait until you overheat.
Furthermore, it has to be either, PS fluid, motor oil, brake fluid, coolant, or tranny fluid or dif oil. Rule them out, one by one. Brake fluid has a very distinguishable smell. As does coolant. Toyota calls for using tranny fluid in our PS systems so if you narrow it down to tranny fluid it would be either of those two. Dif oil is a lot thicker and also has a distinguishable smell. One other thing, leaks don't fix themselves, they usually get worse.
PS. I just re read a little of this thread an no where have you ruled out condensate from your AC system.
Edit again: You said it's not staining your driveway? In that case you can rule out any of the oils and really even the coolant unless your's is super diluted. I'm saying it's AC condensate, because of this and because you said it went away for a few weeks.
