http://pcod.es - share, track and promote iOS promo codes (could easily be expanded to share promo codes for anything in a controlled way). Ruby on Rails.
Domain only: pushp.in - I have an offer for this so you'd need to be quick.
I've considered that, but the last time I tried you couldn't use the words iPhone or iPad in a Google Ad. Has that restriction gone away, or how do you work around it?