@Vladislaus: the extensions are protected, as is the x86 instruction set (and the x64, too), however they are only protected against hardware implementations (they're copyrighted). As such, writing an emulator doesn't require licensing, as Bosch and Qemu are proof: they are open-source x86 andx86-64 emulators. Qemu is also able to emulate ARM.
@ashesofempire4: sorry to disappoint you, but when you say: "can you run Linux apps on Android?" The answer isn't, as you think, no - it actually is yes. As a matter of fact, this is the main reason for rooting an Android device. And currently, the biggest example is a prototype phone, demonstrated by Canonical, that boots the Android ICS kernel (which is Linux + croutons) and is able to run, side by side, the Android interface (with phone calls, etc.) and the Ubuntu desktop (with LibreOffice, desktop Firefox...)