Server 2003 Roles

I would like to know if its possible to use a single win 2003 server for multiple roles like Domain server, mail, file & print and web. I have a client who needs a company server (one) currently for most of the above services i mentioned. Overall thing is also to build a company web site that can either be hosted elsewhere or on the single server. The company currently has 6 users who will use most of the servers services for e-mail, file & printer sharing, internet.