vmware allows "switching" between different operating systems, like the old guest operating systems on IBM 360.
IMO - the simplest install is to get cygwin. It is a unix that runs under Windows, uses windows dll's, lets you see all the disks, etc.
http://www.cygwin.com/mirrors.html
If you are not running a trial of vmware, (ie., you piad for vmware) you should consider a linux distribution like ubuntu, debian, or fedora core 6. Ubuntu is the most windows-like among those. Otherwise try cygwin, it does not require formatting disks. Unless you add an external USB disk or something, I do not know how you can possibly install any unix at all.
I may be wrong, but I do not know of any unix that that can natively use NTFS or FAT32 instead of ext2 or ufs, etc. (unix flavors of native filesystems).
I could be wrong because most of my time has been on big multiuser boxes.