The information is found in Books Online, which is Microsoft SQL Server's documentation. It usually installs with the client tools and/or a server install.

You said SQL Server 2003. If you mean SQL Server 2005 (it went from 2000 to 2005), you can find it here:

SQL Server 2005 Books Online

from that link you can find Books Online on MSDN or download a version to install on your computer.

If you mean SQL Server 2000, a downloadable version is here:

SQL Server 2000 Books Online Download

It is also available on-line on MSDN.