What is this drip?
 

I'm doing my coolant flush right now. I put in the prestone flush, drove for a week. Drained, added distilled water, ran it with the heater on blast, cooled, added more distilled water, ran it with heater on blast.

The first time I had the heater running, I didn't notice the drip, cuz I actually drove to put some gas in. This time I ran it in the garage and noticed a pretty steady drip coming from the pics below. Please help in identifying..I am a wannabe home mechanic...so I'm trying. Thanks in advance. i hope i'm being paranoid and its not something too difficult.

http://i57.photobucket.com/albums/g2...a/CIMG1844.jpg
http://i57.photobucket.com/albums/g2...a/CIMG1843.jpg
http://i57.photobucket.com/albums/g2...a/CIMG1842.jpg

All photos taken from underneath (obviously i guess)

floorboard on the passenger side wet?...possibly heater core?

floorboard isn't wet. it's just dripping before what I guess is the firewall...

Truck equipped with A/C?
If it's just plain water, my guess is the evaporator drain.

shouldn't it drip out the end of the hose and not where it comes out of the wall?

possible blown head gasket that looks like coolant to me. that looks exaclaly like when mine blew.

i don't have any other symptoms of a blown head gasket.