you can use it in vista by checking xp sp 2 compatibility, i also choose to run this app as an administrator so that I don't have to agree to the changes it makes (registry settings etc)
the official line from the company was that an upgrade would be made available in "early 2007"
which could be whenever, they weren't exactly forthcoming with the upgrade for x64 machines, although I hope it means we don't have to wait much longer than say the end of June.
you can try to wheedle this information out of the company, but unless you speak German don't count on much of a reply.
I read in a review that Windows Vista was supported by TuneUp Utilities 2007 so I downladed it on a month's trial. However, it appears that it there is no Vista support at present. They promise a free update to support Vista in "early 2007".
As usual, I've had no luck when emailing so called product support. Does anyone know when this update will be released?