Installation of Windows SharePoint services 2007 Beta II is not as simple as the previous version. The installation steps are not available in the SDK Help file so you have to look around for that. Here is the link to the installation guide.
http://officebeta.iponet.net/en-us/techcenter/HA012258141033.aspx
During the installation you will require to download Windows Workflow foundation as well here is the link to download and install the latest bits of WWF 2.2 for Visual studio .net 2005.
Regards,
Jerry