What are brake guide pins?

I have squeeky breaks and someone recommended greasing the guide pins? Where/what are the guide pins? I need a good description, or picture. Any help would be greately appreciated, thanks.

not sure what that means. I've delt with MANY different gm disk brakes, and i have never seen any "guide pins" sometimes the pads come with a tab on them that will touch the rotor and squeek to let you know that you pads are seriosuly low. but other than that, I'm not sure what the hell that is

The guide pins are the bolts you take out to remove the caliper.
They ride in a rubber boot and "float" on them (if thats a good description)
Changing your rubbers and greasing the pins will help keep the caliper from staying on one side or the other too much.
Lots of people ignore this step when changing the pads but it can help alot.
Anybody else feel free to explain this better. :)

The guide pins are the bolts you take out to remove the caliper.
They ride in a rubber boot and "float" on them (if thats a good description)
Changing your rubbers and greasing the pins will help keep the caliper from staying on one side or the other too much.
Lots of people ignore this step when changing the pads but it can help alot.
Anybody else feel free to explain this better. :)

Thanks, this sounds right, Google failed me on this one...