I doubt they will be making one specifically for the Beta versions, they
probably just expect you to post to
microsoft.public.internetexplorer.general
or maybe one of the IE6 groups for now. I haven't checked, but there might
be a messageboard somewhere that is specifically for IE7. I think the reason
for not having a Beta newsgroup is because they want you to report any
problems/suggestions directly to them using whatever it says on the page the
Beta was downloaded from, because they don't expect regular users to try to
use the Beta version, it is intended for developers and IT people only.