The first Feature Pack for SQL Server 2005 has been released.

According to the downloads page it contains:

The Feature Pack is a collection of standalone install packages that provide additional value for SQL Server 2005. It includes:

  • Latest versions of redistributable components for SQL Server 2005
  • Latest versions of add-on providers for SQL Server 2005
  • Latest versions of backward compatibility components for SQL Server 2005

In plain English, it is a self contained set of SQL 2000 bits so you don't need to install SQL 2000 for full backwards compatibility and runtime support.