Pre-releases of Quantal Quetzal are *not* encouraged for anyone needing a stable system or anyone who is not comfortable running into occasional, even frequent breakage. They are, however,recommended for Ubuntu developers and those who want to help in testing, reporting, and fixing bugs as we work towards getting this release ready.
Alpha 3 is the third in a series of milestone images that will be released throughout the Quantal development cycle, in addition to our daily development images. The Alpha images are known to be reasonably free of showstopper CD build or installer bugs, while representing a very recent snapshot of Quantal.
Download Ubuntu 12.10 (Quantal Quetzal) Alpha 3
You can download them here:
http://cdimage.ubuntu.com/releases/quantal/alpha-3/ (Ubuntu Desktop, Server)
Additional images are also available at:
http://cloud-images.ubuntu.com/releases/quantal/alpha-3/(Ubuntu Server Cloud)
Alpha 3 includes a number of software updates that are ready for wider testing. This is an early set of images, so you should expect some bugs.