There are a plethora of iPhone app directories and platforms that try to make sense of the 100,000 apps in the App Store ecosystem. We've recently written about Appolicious, Chorus, and others that have customized app directory and recommendations services. Now, directories are beginning to incorporate Android app directories into their platforms. Mplayit, which recently launched a comprehensive iPhone app discovery directory within a Facebook app, is rolling out a catalog of the over 16,000 Android applications on the social network. Similar to its iPhone app directory, Mplayit’s directory of Android apps includes a dedicated page for each app where Mplayit will post videos of the app (created either by the developer or pulled from YouTube), a detailed description of the app and reviews. You can also click to buy the app from the Android Market.