Service Packs
Note: If you use SQL Server authentication, also known as standard security, with SQL Server 7.0 or SQL Server 2000, read FIX: Service Pack Installation May Save Standard Security Password in File in the Microsoft Knowledge Base.
SQL Server 2000
If you are using SQL Server 2000 and have applied SP3, you do not need to apply SP3a. SP3a is only for SQL Server 2000 users who have not applied any versions of SP3. However, you should use SP3a rather than SP3 moving forward.
Reporting Services
Notification Services
SQL Server CE
SQLXML 3.0
SQL Server 2000 Driver for Java Database Connectivity (JDBC)
Microsoft Data Access Components (MDAC) 2.6
Documentation
Download the Books Online, guides, and help files you need to make running SQL Server 2000 easier.