As it stands youll need to jailbreak the 2.0 firmware to use mobilecast. I havent looked into it much yet, but I doubt well be able to offer mobilecast (in its current form) via the app store as we use a lot of undocumented apis that are not part of the official SDK.
I dont know how strict apple will be about the use of undocumented apis, so it might be worth giving it a shot and submitting mobilecast as an official app.
Given that the MC source is open source I think well continue to offer the app for free even if its accepted into the apple app store.