VMware Workstation 5.5
This is desktop virtualization software for software developers/testers and enterprise IT professionals.
It allows users to run multiple x86-based operating systems, including Windows, Linux, NetWare, and Solaris x86, and their applications simultaneously on a single PC in fully networked, portable virtual machines- no rebooting or hard drive partitioning required. It drastically accelerates the software development/testing process, increases user and team productivity, and enables hardware consolidation.
A 30-day serial number is required to use the software. After installation, on the user interface go to Help > Enter Serial Number and click on "Get Serial Number"