We launched an app discovery service at http://www.tekiki.com
and would love feedback. We show games that went from paid to free, but with two twists: (1) we only show apps rated 4+ stars; and (2) we make it faster for users to browse showing how many apps went free in each category, from action to word. Other sites usually lump all games into one category, meaning you may wade through 200 apps even if you only care about 200 games.
We're also looking for great games to feature. If you have a free game, or are willing to make the game free, and are interested in learning more, please post something here. We feature games for free.