The EBS Productgroups published a script on their blog to multi assign EBS 2008 CALs to Users and/or devices using Powershell:
The PS1 script is available for download here:
The instructions to run the script are:
"1. On the Management Server, right-click the icon for Windows PowerShell and choose “Run as administrator”
2. Save the file locally to disk, right-click on it, choose properties, and click on the Unblock button
3. In the PowerShell command prompt, execute the script by navigating to where you saved the file and typing
(for standard CALs; substitute premium as appropriate)
4. Open the EBS Administration Console, navigate to the Licenses tab, select User Licenses, and review the results. Ensure that users have the correct edition."