Ubuntu Server 12.10 Alpha 1 (Quantal Quetzal) is an important milestone for Canonical, mainly because it's aimed at businesses and because the previous version was recently certified by HP.
Being just the first alpha version in a long line of development versions, there aren't many updates. In fact there is only one change from the the previous version and that is the size of the ISO image. Canonical is targeting a CD size image (703MB).
According to Canonical, the primary installation method is the 64-bit release. The i386 version might not make it to a stable version as the company is still assessing if the 32-bit server platform is still needed.
Download Ubuntu Server 12.04 Alpha 1 right now from Softpedia. Remember that this is a alpha version and it should NOT be installed on production machines. It is intended for testing purposes only.