After installing Office 2012 on my new installation of Windows 8 Release Preview I felt brave enough to go look at SharePoint 2013.
Microsoft provides a link to the TechNet Evaluation Center
The serial key is also provided.
But if you are lazy
Product key: 6RNT8-XV26M-GWH36-VMGQH-94MMH
I am very excited to test drive this puppy and hopefully I will blog about it at some stage, well sooner or later I am bound to.