You have two options here….
1. If you want to keep Win 2003 as the host OS then they would have to use VMware Server
2. If you are willing to replace the host OS with ESXi then use that and install all the apps inside new guest VMs inside ESXi
Hope that helps!
David Davis, VCP, CCIE
Director of Infrastructure
Train Signal – The Global Leader in Professional Computer Training
<a href=”http://www.trainsignal.com”>www.TrainSignal.com</a> – VMware Server & ESX Server Video Training Author
#1098 of Inc. Magazine’s 5000 Fastest Growing Companies
Agree with Mr. Davis. If cost is an issue with your company, then go with the free VMware Server. VMware Server is an application base virtualization that would run ontop of your Windows 2003 Server and will host your servers. Since you are new to virutalization I would first start off with VMware Server and then if you feel you need more features like high availability, you may want to lean towards VMware ESX or ESXi.