Dang, I was searching for that :) That's where we got started.
We also sent promo codes to..ars technica, engadget, appleinsider, tuaw, gruber over at daring fireball, chris pirillo (plus a few extra codes to give away to his viewers, which was additional publicity), and some others I can't remember.
Depending on your application you may want to submit to sites specifically catering to your audience. I know some of our promo codes went to people at IRC news/review sites since Colloquy is an IRC client. And as an example, if your app was a game, you'd want to send a code over to sites like toucharcade, run by the same guy behind macrumors, who also frequents hn as 'arn' :)