Originally with the Ubuntu SecureBoot plans unveiled back in June, they planned to not use GRUB2 when dealing with UEFI SecureBoot. Canonical's position was that the GPLv3-licensed boot-loader might lead them to needing to disclose their private SecureBoot key, thus compromising the support. The plan was to use the EFILinux boot-loader instead as it's more liberally licensed from Intel.
However, after Canonical talked it over with the Free Software Foundation and their OEM partners (along with taking heat from many others for moving away from GRUB2), they changed their minds. GRUB2 is going to be the default boot-loader for Ubuntu 12.10 and Ubuntu 12.04.2 LTS.
More information on this boot-loader flip-flopping are mentioned in this Canonical blog post.