RED's new Meizler Module was recently introduced, and it does almost everything you think a module should be able to do. It's wireless functionality and proxy capabilities are the main selling point, but RED is also developing their own app that allows control of a RED EPIC or SCARLET through an iPad, iPhone, or iPod Touch. Here is another video from Sean Ruggeri at RED giving a brief overview of the Meizler Module as well as the new REDsync app:
The REDsync Master is an entirely different device, and not another module that attaches directly to the RED body. To actually be able to use the REDsync app, it seems like it requires the Meizler Module, along with the REDsync Master -- though I'm not sure if that will be the case (or always be the case). There are many productions that would benefit greatly from the ability to use the REDsync app, as it gives tons of metadata information -- not to mention the ability to control remotely many functions and settings of the camera.
From what I can tell, none of these are actually available yet, but we should be seeing them sooner rather than later. If you're in the market for a Meizler Module, and you need the functionality, it's up in the RED store right now (available from the link below), but doesn't look like it's shipping just yet.