As you may have noticed in the Gingerbread video found earlier on the Google Hong Kong account, there was a new tab in the Android Marketplace showing similar applications. We presumed it would make an appearance with the release of Gingerbread itself, but an XDA member noticed that they had it on their own Nexus One, running CyanogenMod. The poster, utcarbs, had just updated his Flash Player to the latest version, which seemed to trigger the tab's appearance. Having just done the same process on my own Nexus One, I can confirm this new feature's availability:
Flash Player was updated only 6 hours ago according to AppBrain, so there will be plenty of Android 2.2 users out there yet to grab the latest version. Go out there and get it guys, and let us know if the Similar tab is appearing for you too.