No, the clients limit for Shared Folders and Printers on any Windows Server is unlimited by default.
But it is also "unlimited" if you use a Print Server, that is a much easier and cheaper long and short term solution than buying and setting up a Windows 2003 Server just because of a printer.
Also, there are some tricks online you can try to increase the number of connections on your Windows XP machine to up to 50 users.