i already have xp and vista installed on my pc as dual boot, i have 4 gigs of ram, will i be able to install windows 7 as well, or do i need a new drive for that?
Yes, m' dear... I ran 3 OSes on my rig before without issue, so if you have enough hard drive space to create another partition, you can install Win 7 on your PC alongside the others.
will sk6 be used to skin windows 7? or will there be a new sk for that?
Given there are some major UI changes in Win 7, there would be some necessary updates to SKS6 to accomodate them... though I imagine that Stardock would ultimately release a new version to take better advantage of Win 7's features.
does anyone have a general idea of the cost of w7 basic (or home?)
MS has not released any firm indication of pricing as yet... let's just hope they take harder financial times into consideration and put a fair/reasonable price on it. However, the 'basic' edition will be a limited release to emerging markets and you're unlikely to see it unless it comes pre-installed on an OEM machine. Price-wise, you would most likely would want to go with Win 7 Home Edition over the Professional Edition... these will be the two mainstream retail versions, with the more expensive Win 7 Ultimate Edition likely to be an 'order in' option.
Hope this helps.