South Park now has an official app that was announced during the South Park 20 experience at Comic-Con in San Diego.
You can see clips, set reminders when episodes come on and view character quotes. Starting in September you can login with a TV Provider (USA Only) to watch South Park episodes from the app.
Just search for "The Official South Park App" on Google Play or the Apple App Store to download. Remember you can also view South Park Archives on your mobile device by going to the wiki on your mobile device's browser. The mobile version of SPA does not allow editing, but you can still read articles, which have been optimized for mobile device reading.