I don't have a pic of this, but I'm hoping you can tell me what it is by the description.

Midway back on the drivers side under the truck is a black box with a couple of hoses coming out of it. There is a leak coming from one of the hoses. It looks like I can just tighten the clamp and be ok, but I don't know what that part is.

I wanted to look it up, but not sure where to start since I can't identify it. LOL

 

that is probly the evap canister. it traps all of the fuems from the gas tank

 

it's called a charcol canister...or as the parts book calls it "vapor canister"...same difference...they had 2 different styles from 02-04 a round and square one

 

So what would be leaking from it?

Thanks for the ID btw.

 

Evap canister I would agree, probably leaking condensation. I'm really shocked your not getting a p04xx CEL code. But I've heard the '03s don't have a lot of the emission crap programmed in the PCM, hell you lucky stiffs don't even have an EGR to have to mess with.
Here is a diagram of your Evap System:

 

yep, it's leaking at number 9... but mine is a bit different I think. It looks like mine has two rubber hoses coming out of it.

The fluid that is leaking is more like a lubricant... not condensation.