I was suprised that I couldn't find a complete list of "build number to service pack" mappings for SQL Server 2000 Reporting Services anywhere... So, here they are:
SP2 with KB901383 Hotfix: 8.00.1042.00
SP1 CTP: 9.00.1528.00
To check your version just surf to http://yourServerName/reportServer ....then scroll to the bottom of the page.