Whenever you install OCS 2007 in a lab domain you need to generate users for your environment. Ram Ojha har created a cscript that does the following:

• It’ll read the csv file you create
• It will create the user.
• It’ll read display name from the file and write FirstName, LastName and DisplayName of the user.
• It’ll set the TelephoneNumber of the user.
• It’ll enable the user for Office Communications server
• It’ll set the SIP address (msRTCSIP-PrimaryUserAddress)
• It’ll assign the user to a pool (msRTCSIP-PrimaryHomeServer)
• It’ll enable the user for Enterprise Voice (msRTCSIP-OptionFlags)
• It’ll assign the Line URI (msRTCSIP-Line)

Head over to his post to download the script and see how to modify it to support your needs: http://blogs.technet.com/ramo/archive/2009/08/20/script-to-create-users-in-ad-and-enable-it-for-office-communications-server.aspx