Do I have LCD or LED??

You're confused on a matter of acronyms. LCD stands for Liquid Crystal Display, which is what the screen is made of. LED stands for Light Emitting Diode, which is the backlight system that allows you to see what your LCD shows. The other backlights (the one that is in the non-high res 17 inch model) use CCFL, which stands for Cold Cathode Fluorescent Lamp. Think of that as similar to a fluorescent tube light. The LED models are more energy efficient, provide a cleaner light, and last much longer. If you have the high resolution 17 inch, then it is indeed using LED backlights, as there is no other option.

You have an LCD screen with a LED backlighting. It may sound confusing, but that's what people mean by "LED Screens." =)

Essentially, before the diodes have been illuminated with a special type of fluorescent light, I believe. Your computer uses LEDs, which use less energy and allows it to be a bit sharper.

"...If you have the high resolution 17 inch, then it is indeed using LED backlights, as there is no other option."

Its the only option available now, but apple previously offered the 17" hi-res option before the last update to the MBPs. I know because I placed an order for one the day before they updated the store and they gave me the opportunity to update to the latest and greatest hardware (incl. LED) before it shipped. Were they always using LEDs and not advertising it? I was equally confused about the missing LED label and have been searching for answers to why they offered the updates and stiffed me.

The previous hi-resolution model (2.4 Ghz) was not an LED backlight. The only 17in one with the LED is the current high resolution.
Apparently, for packaging simplicity, the boxes (at least for mine, a mid-2007 15 inch) still had the fluorescent mercury warning on them, but it is indeed an LED.

How can I tell which MBP I have?

I purchased mine in November of 2007 and it is a High Res model.

About this Mac says:
LCD
1920 x 1200

Mine is a 2.4 GHZ and came with the 160 Gig 7K drive. The Model Id says: MacBookPro3.1

Thanks,

Kirk

That's not an LED model, sorry!

The sales guy told me it was, but I didn't know it was better or not.

Was my first Mac purchase, and my first laptop. Got the High Res screen at the recommendation of my Photoshop friends.