Microsoft Office Licensing for Terminal Server

A client of our is looking to invest into upgrading to Microsoft 2010 Office on their terminal server.  They currently have a Microsoft E-Open licensing agreement for other software and an account setup.  My question is how does Microsoft handle terminal server licensing for Microsoft Office copies when multiple users use the same machine?  Would the client be required to purchase one copy for each user that is expected to be using Microsoft Office on the terminal server or would they be able to buy one copy of Microsoft Office and have it installed and all users be able to use it?

I just want to make sure I correctly inform our client as to Microsoft's terms and agreements with terminal server licensing I wasn't able to find clear cut information on Microsoft's site.

Thank you for your advice on this matter.