Although this is not a supported scenario, there is a way to install MOSS 2007 onto Windows 7 Release Candidate (build 7100). Here are the steps:
Now you need to slipstream the installation packages (if you try to run the installer without SP2 slipstreamed, you will be blocked (KB 962935)
To create the slipstream package, follow the steps in http://technet.microsoft.com/en-us/library/cc261890.aspx. Basically, you need to open a command prompt and execute the following commands:
Delete Wsssetup.dll because it may conflict with Svrsetup.dll. Having both Wsssetup.dll and Svrsetup.dll in the updates folder for a slipstreamed installation source is not supported.
Run the SetupLauncher from C:\Program Files (x86)\WssOnVista\Setup
Locate the setup.exe in your installation folder.