SUSE has given some indication of how it will implement Secure Boot: http://www.suse.com/blogs/uefi-secure-boot-details/
Basically, SUSE will take an approach similar to the one taken by Red Hat regarding Fedora (including using a shim based on Fedora's), but with some improvements. It's worth reading the article for its explanation of SUSE's clever approach. There's also a brief article by Red Hat's Matthew Garrett discussing this: http://mjg59.dreamwidth.org/15818.html
From what Garrett says, Fedora will likely adopt the improvements that SUSE came up with. It sounds good, and should make things easier for users who want to manage their own keys with Secure Boot enabled (e.g. to install custom kernels).
I suspect as the intricacies of Secure Boot are examined closer, there could be even more ways discovered for users of alternate OSes to do what they want without having to disable Secure Boot. As it is, the three largest Linux distros (Fedora, Ubuntu, SUSE) have adopted concrete plans for dealing with Secure Boot, and I suspect more will follow suit.