The Linux 3.6 kernel is one day old but there's already lots of interesting ARM work happening for 3.7. ARM Xen virtualization support is going into the Linux 3.7 kernel, per the pull request this morning that Konrad has accepted as the Xen kernel maintainer, and now we have AArch64.
ARM originally published the Linux kernel port of AArch64 back in July and since then they have been revising this ARM 64-bit architecture support for the Linux kernel. The work has been ongoing but now with the Linux 3.7 kernel it will be part of the mainline tree.
The pull request for ARM64/AArch64 can be found on the kernel mailing list by Catalin Marinas. Currently implemented for this Linux kernel architecture port is 39-bit address space for user and kernel space (each), 4KB and 64KB page configurations, 32-bit compatibility for user-space applications (ARMv7, EABI builds), flattended device tree support (a requirement for AArch64 platforms), and ARM generic timers support.
This Linux kernel support for 64-bit ARM will surely mature in the coming kernel releases as it will still be quite a while before any ARMv8 hardware is actually on the market. There's also ongoing AArch64 developments within GCC and other areas. Debian is hoping to have Debian for 64-bit ARM ready by their next major release to succeed Squeeze.