Since BP6.Com was down for a while we couldn't post the release of SP4 for Windows 2000. Released on June 26, 2003, here is some info from Microsoft.Com:
Windows 2000 Service Pack 4 (SP4) provides the latest updates to the Windows 2000 operating systems. These updates are a collection of fixes in the following areas: security, application compatibility, operating system reliability, and setup. Windows 2000 SP4 is a recommended update that includes the updates contained in previous Windows 2000 service packs.
To determine whether to install Windows 2000 SP4, Microsoft recommends that you review the Windows 2000 SP4 documentation in the For More Information section below.
Depending on the installation you choose the Service Pack size ranges from about 15megs to 120megs.