The process could be automated using the "NET USER" command, which creates user accounts. However, all accounts will have a blank password and will only belong to the "Domain Users" group. If this is OK, then I would use a text editor and copy/edit a list such as:
NET USER User1
NET USER User2
NET USER User3
I believe there is a way to import the user names from a list, but it escapes me at the moment. Check TechNet at Microsoft.com - you should be able to find it there...