Microsoft have (or at least did - I can't connect to the site at the moment)
the SKU's listed up at:

http://windowshelp.microsoft.com/Windows/en-US/help/c0680472-bb5f-4a9c-9480-b16a
b3eeb8f51033.mspx

Hi tony,

The official announcement has now been published:
http://www.microsoft.com/windowsvista/versions/default.mspx

"The five different versions of Windows Vista are designed to fit
the way you intend to use your PC:

Windows Vista Business
Regardless of the size of your organization, Windows Vista Business
will help you lower your PC management costs, improve your security,
enhance your productivity, and help you stay better connected.

Windows Vista Enterprise
Windows Vista Enterprise is designed to meet the needs of large global
organizations with highly complex IT infrastructures. Windows Vista
Enterprise can help you lower your IT costs while providing additional
layers of protection for your sensitive data.

Windows Vista Home Premium
Whether you choose to use your PC to write e-mail and surf the Internet,
for home entertainment, or to track your household expenses, Windows
Vista Home Premium delivers a more complete and satisfying computing
experience.

Windows Vista Ultimate
If you want all of the best business features, all of the best mobility
features, and all of the best home entertainment features that Windows
Vista has to offer, Windows Vista Ultimate is the solution for you. With
Windows Vista Ultimate you don't have to compromise.

Windows Vista Home Basic
Windows Vista Home Basic is designed to deliver improved reliability,
security, and usability to home PC users who just want to do the basics
with their PCs."