AS you already know SharePoint 2010 is in Beta release and it only supported for 64-bit OS. I am sorry for them who are looking for a SP2010 version for 32-bit OS. Here i will explain what you need to do to prepare your environment before installing SP2010
Physical Machine:
As you already know that SharePoint can be install in 64-bit Windows 7 so your physical machine can be with the following configuration:
Processor: 64-bit, four-core, 2.5 GHz minimum per core
Ram: 4 GB for developer or evaluation use
HDD: 80 GB for installation
OS: Must be Win Server 2008 Standard with SP2/R2 x64 / Windows 7 x64 / Vista SP2 x64
Most developer want to setup it on Windows 7 / Vista which was not supported in MOSS 2007
This would be enough to install your SharePoint 2010
References:
http://msdn.microsoft.com/en-us/library/ee554869%28office.14%29.aspx
http://technet.microsoft.com/en-us/library/cc262485%28office.14%29.aspx
http://www.sharepointdevwiki.com/display/sp2010/Building+a+SharePoint+2010+Development+machine