1) radiator - check for leaks on driver's side above the red drain knob. I've seen three leaking there. Could get lucky and have a leak from a loose pressure switch or coolant temp sensor (also on that side)
2) HCV - search for the heater control valve ya will find lots about it.
3) heater core - look for a small tube in the floorboard above the passenger side of the tranny. It comes out thru a grommet. This is the drain from the heater core box, if it is dripping antifreeze thats where it is coming from.
4) Oil Cooler / seal plate - will cause leaks out the back side of the engine
5) Coolant crossover - the bolts with the metal / rubber seals can leak
6) a multitude of hose connections - not a simple 'it goes in here comes out there' setup - large metal coolant pipe has a seal at the back of the block; hoses for the two electric water pumps; intake manifold inlet and outlet...
7) Mechanical water pump - behind timing chain cover. Could leak out shaft seal or the O-ring seal on the backside.
Head gasket leak? Be careful if a mechanic suggests that. Sure it happens but there are a lot of other sources to weed thru first. If you have rode the redline on the temp then bets are off.
FYI second week and into the second thousand on the now happy refurbished Cat. 95 outside, 65 inside, and the heat gauge at half. Never thought I'd see it
Coolent level drops!! 
