I'm working on an application that requires support for forward locking of media files on Android (1.6 and above). Of course, there appears to be no documentation in the APIs on how this might work.
The two questions I have are firstly whether forward locking is supported on Android (and in which versions of the platform) and secondly how to implement it in a program that, for example, downloads DRMed ringtones and wallpapers.
Android isn't that big on DRM, because of the open source heritage of the product. I think you'll have to implement any DRM solution yourself.