Now that Microsoft has made Office 365 Home Premium official, I'm going to jump in and start my subscription for my Windows 8 Pro install.
Unlike the traditional retail versions of Office, Office 365 Home Premium is a subscription service that you must pay for monthly, $9.99, or annually, $99.99. The first month is free. If this works out like I think it will, I'll be purchasing the annual subscription next month.
You can also install Office 365 on a mix of up to 5 Windows and Mac OS X PCs. You should also be able to upgrade Office on your Surface RT or Surface Pro, but I'm not 100% sure on that just yet. If you're on a Mac like me, your Office 365 subscription also gives you access to Office 2011: Mac Edition. (It counts toward one of your 5 installs.)
For more details, check the Microsoft Office website.
Here are a few additional screen shots after having installed Office 365 on Windows 8 Pro.