One of the meetings held this week during the Ubuntu Developer Summit for the Ubuntu 10.10 planning in Belgium was about Btrfs. During this session the developers discussed adding Btrfs support to GRUB2, whether or not Btrfs encryption is possible initially, an option to enable the Btrfs zlib compression, and other details.
Unfortunately, Btrfs will not be receiving much love in the Ubuntu land anytime soon. The GRUB2 boot-loader in Ubuntu 10.10 may receive support for booting from a single Btrfs device, but much of the work doesn't look like it will come to fruition until 2011 and 2012.
With Ubuntu 11.04, developers are hoping that the LiveCD will use Btrfs and to have Btrfs enabled as an experimental file-system to allow development of the Btrfs tools required to ship in Ubuntu 12.04 LTS. In other words, while Fedora has supported installing to a Btrfs root file-system for more than a year, it will still be a year or two before Ubuntu receives such support.
The details for this planning can be found on the Ubuntu Wiki via the MaverickBtrFsSupport page or on Ubuntu's Gobby server via the foundations-m-btrfs-support document.
Perhaps in Ubuntu 12.10 or 13.04 we will see Btrfs become the default Ubuntu file-system.