As most rabid Linux zealots know, Linux ports are available on several architectures - x86, Alpha, Sparc, PowerPC, MIPS, and m68k, among others. In theory, the Linux IPv6 code is architecture-independent. It is known to run on the Alpha platform, and there are rumors of it working on Sparc. However, unless stated otherwise, all architecture-dependent information in this FAQ (patches, etc...) is for the x86. I'm sure that as the IPv6 code matures and Linux develops, all Linux platforms will come to support IPv6.
As of this writing, the latest experimental Linux kernel is 2.1.44, but I'm sure that's changed by the time you read this. IPv6 support is now supported in the kernel as a compile-time option. The goal is to bring a stabilized IPv6 to 2.2.0, when it arrives.
There are several useful mailing lists that you may want to subscribe to:
This list is for people involved in, or just plain interested in, the work being down to bring IPv6 to Linux. This is the place where the developers hang out.
Subscription Requests to: firstname.lastname@example.org.
A general mailing list about Linux networking - subscribe via email@example.com.
Similar to Linux-net, except (you guessed it!) about issues related to the Linux kernel. Subscriptions to firstname.lastname@example.org.