Contributed By: Jeff LeBlanc [MSFT]
Yes SMS 2.0 will run on Windows Server 2003 but requires SP5, or SP4 with some additional hotfixes. I'd recommend SP5.

See the Microsoft "Support for New Operating Systems and Applications" site for more information

http://www.microsoft.com/smserver/techinfo/deployment/20/deployosapps/newsupport.asp