Is it "Hear, hear!" or "Here, here!"?

Factual Questions
1

When one is attempting to express support for a statement made by another, does one say “Hear, hear!” or “Here, here!”?
The latter makes more sense to me, but I’m not certain about this.

2

It’s “Hear, hear!”

This from the Straight Dope mailbag.

3

It’s “hear, hear!” as in “listen to what is being said!”.