Here the official announcement:

The Ubuntu team is proud to announce the Release Candidate for version 6.10 of Ubuntu, Kubuntu and Edubuntu - codenamed "Edgy Eft". The Release Candidate includes installable live Desktop CDs, server images, alternate text-mode installation CDs and an upgrade wizard for users of the current stable release.

We consider this release candidate to be complete, stable and suitable for testing by any user.

The final release of version 6.10 is scheduled for 26 October 2006 and will be supported for 18 months on both desktops and servers. Note that the current stable release (6.06 LTS) is a long-term support release, and so users requiring a longer support lifetime may choose to continue using that version rather than upgrade to 6.10.

Before installing or upgrading to "Edgy Eft" make sure to read
https://wiki.ubuntu.com/EdgyReleaseNotes

Upgrade information for users of Ubuntu and Edubuntu 6.06 LTS
--------------------------------------------------------------

* NOTE: This procedure upgrades your system over the Internet,
which requires a large download of several hundred megabytes.

* Because this is the Release Candidate, you need to invoke the
update manager explicitly. To do this, press Alt-F2 (or open a
Terminal using Applications -gt; Accessories -gt;Terminal)

gksudo "update-manager -c -d"

This step will not be necessary on the final release.

* Make sure you are up to date - click the "Check" button. If you are
connected to the network, Update Manager should now tell you about
the 6.10 ("Edgy Eft") release

* Further information about this upgrade procedure is given at
https://wiki.ubuntu.com/EdgyUpgrades


Upgrade information for users of Kubuntu 6.06 LTS
-------------------------------------------------

* NOTE: This procedure upgrades your system over the Internet, which
requires a large download of several hundred megabytes.

* In Konqueror go to /etc/apt, right click on sources.list and choose
Actions -gt; Edit as Root

* Change all instances of dapper to edgy

* Launch a console with KMenu -gt; System -gt; Konsole

* In the console run: sudo apt-get update

* In the console run: sudo apt-get dist-upgrade and follow the
prompts to upgrade

* In the console run: sudo apt-get install kubuntu-desktop python-qt3
python-kde3 and follow the prompts to install

* Reboot your computer


To Get the Ubuntu 6.10 Release Candidate CD
-------------------------------------------

To perform a new installation or try out 6.10 "live" from CD, download the Ubuntu 6.10 Release Candidate (choose the mirror closest to you):

Europe:
Ubuntu:
http://de.releases.ubuntu.com/6.10/
http://nl2.releases.ubuntu.com/6.10/
http://se.releases.ubuntu.com/6.10/

Kubuntu:
http://se.releases.ubuntu.com/kubuntu/6.10/
http://de.releases.ubuntu.com/kubuntu/6.10/
http://nl2.releases.ubuntu.com/kubuntu/6.10/

Edubuntu:
http://de.releases.ubuntu.com/edubuntu/6.10/
http://nl2.releases.ubuntu.com/edubuntu/6.10/
http://se.releases.ubuntu.com/edubuntu/6.10/

Australia:
Ubuntu: http://au.releases.ubuntu.com/6.10/
Kubuntu: http://au.releases.ubuntu.com/kubuntu/6.10/
Edubuntu: http://au.releases.ubuntu.com/edubuntu/6.10/

France:
Ubuntu: http://fr.releases.ubuntu.com/6.10/
Kubuntu: http://fr.releases.ubuntu.com/kubuntu/6.10/
Edubuntu: http://fr.releases.ubuntu.com/edubuntu/6.10/

The Netherlands:
Ubuntu: http://nl.releases.ubuntu.com/6.10/
Kubuntu: http://nl.releases.ubuntu.com/kubuntu/6.10/
Edubuntu: http://nl.releases.ubuntu.com/edubuntu/6.10/

Poland:
Ubuntu: http://pl.releases.ubuntu.com/6.10/
Kubuntu: http://pl.releases.ubuntu.com/kubuntu/6.10/
Edubuntu: http://pl.releases.ubuntu.com/edubuntu/6.10/

United Kingdom and Rest of World:
Ubuntu: http://releases.ubuntu.com/6.10/
Kubuntu: http://releases.ubuntu.com/kubuntu/6.10/
Edubuntu: http://releases.ubuntu.com/edubuntu/6.10/

Please download using Bittorrent if possible.


About The Release Candidate
---------------------------------------

The purpose of the Release Candidate is to solicit one last round of testing before the final release. Here are ways that you can help:

* Upgrade from Ubuntu, Kubuntu or Edubuntu 6.06 to the Release
Candidate by following the instructions given above.

* Participate in installation testing using the Release Candidate CD
images, by following the testing and reporting instructions at
http://wiki.ubuntu.com/Testing/Current


Feedback and Helping
--------------------

If you would like to help shape Ubuntu to better meet your future needs, take a look at the list of ways you can participate at

http://www.ubuntu.com/community/participate/

Your comments, bug reports, patches and suggestions will help turn this release into the best release of Ubuntu ever. Please report bugs through the Launchpad Malone bug tracker:

http://launchpad.net/distros/ubuntu/+bugs

If you have a question, or if you think you may have found a bug but aren't sure, first try asking on the #ubuntu IRC channel on FreeNode, on the Ubuntu Users mailing list, or on the Ubuntu forums:

http://lists.ubuntu.com/mailman/listinfo/ubuntu-users
http://www.ubuntuforums.org/


More Information
----------------

Ubuntu is a Linux distribution for your desktop or server, with a reputation for making things "Just Work" out of the box, a fast and easy install, regular releases, a tight selection of excellent packages installed by default, every other package you can imagine available from the network, and professional technical support from Canonical Ltd and hundreds of other companies around the world.

You can find out more about Ubuntu and about this preview release on our website, IRC channel and wiki. If you're new to Ubuntu, please visit:

http://www.ubuntu.com/

Kubuntu is a user friendly operating system based on KDE, the K Desktop Environment. With a predictable 6 month release cycle and part of the Ubuntu project, Kubuntu is the GNU/Linux distribution for everyone.

http://www.kubuntu.org/

The Edubuntu Linux distribution brings the spirit of Ubuntu to schools, through its customised school environment.

http://www.edubuntu.org/

To sign up for future Ubuntu announcements, please subscribe to
Ubuntu's very low volume announcement list at:

http://lists.ubuntu.com/mailman/listinfo/ubuntu-announce