Erm, I believe that there will be only one version of the Windows 8 Alpha released to the public, that being the Developer Preview.
The next version we will see is the Beta.
I'm not really expecting any massive changes, except for modifications to the taskbar, start screen, and explorer (seeing as those are all the focus points)... Though I do kind of feel that desktop icons are a bit redundant now, so I wonder what they'll do with those.