Patrick Rouse has written an article on MSTerminalServices.org that is an architectural overview of VDI, discusses the problems that it addresses and shows the caveats to look out for.

Introduction

In the past few years there has been and continues to be a lot industry buzz around virtualization. At this point most are familiar with the concept of server virtualization and consolidation using VMware ESX or Microsoft Virtual Server. Additionally, many have been successful using application virtualization and streaming technologies like Microsoft Softricity Softgrid to address application compatibility, version control and deployment issues. 

VDI is VMware’s designation for the hosting and virtualization of a individual Client OS like Windows XP Professional, Windows Vista or Linux on VMware ESX. The intent is to be able to deploy, secure and manage enterprise desktops in the data center.

For those used to managing server based computing environments, consisting of Windows Terminal Servers and Citrix, managing VDI is definitely similar task. The difference is that instead of managing numerous centralized, multi-user server operating systems, one would be managing potentially hundreds, or thousands of centralized, virtualized single user operating systems.

Read the article, here.