If you have an MSDN subscription then you are entitled to use up to 200 test users in Terminal Services on any Windows OS in product testing or demonstrations.
First of all have a Windows 2008 R2 server handy. Install the Remote Desktop Services role on it. Then give it the licensing server role.
The Microsoft link tells you how to apply to Microsoft for licensing. Make sure you ask using the form of words in the link as sometimes the call centre staff can lead you to believe that you need to buy CALs.
They will ask you for some details concerning the server and for your MSDN ID.
Ask for per user licensing. They will allocate you ten CALs but with those you can test up to 200 with no problems. You can license 2003 or 2008 servers from your 2008 Licensing Server.