Android is essentially Linux. There are a lot of qualifiers there, and Linux devotees will argue the semantics, but it is generally accepted to be a Linux distribution in the same vein as Debian or Ubuntu. This is why we pay special attention to what the contributors and maintainers of the Linux kernel are up to.
With version 3 of Linux comes better ARM processor support. With version 3.7, that support is almost complete -- which is great news for anyone interested in building a reusable ARM kernel. People like Samsung, or LG, or your favorite Android hacker.
As things stand now, it's fairly easy to build a modular kernel that runs on an X86 device. Those are traditional desktops and laptop computers, ATOM netbooks, and a few smart appliances. But folks working on Linux for ARM devices have had to build and port a kernel for each type of ARM processor, like the Exynos or OMAP SoCs. With a generic ARM kernel, those days will be a thing of the past.
We're not quite there yet, as the 3.7 release only supports a handful of chips from companies like Marvell or Picohip. These are the chips you will generally find on development boards, but Linux founder and guru Linus Torvalds has said that support for many more chips is coming in the next few releases. Once this is accomplished, and Android gets up to speed (Google and their OEM partners usually run about 3 versions behind the current stable), we should see a much more fluid way to support newer devices, and newer software on older devices.