You can install Sun Java System Web Server by downloading it from the Sun Products download web site:
If you have iPlanet Web Server 4.1 already installed and plan to migrate that server to work with Sun Java System Web Server 6.1, shut down the 4.1 web server and save a back up of all its files in the server root.
Direct migration from a version of iPlanet Web Server that is lower than 4.1 to Sun Java System Web Server 6.1 is not supported. You must first migrate your legacy server to iPlanet Web Server 4.1 and then to Sun Java System Web Server 6.1.
You must install Sun Java System Web Server 6.1 in a separate directory. For instance, if a previous version of the web server is installed in C:\netscape\server4, install Sun Java System Web Server 6.1 in C:\Sun\WebServer6.1.
On Windows you can save copies of files added to Winnt/System32 during server installation, and copies of the registry as well. For more information on saving copies of the registry, see your operating system documentation.
If you do not already have a browser installed, install one. For a list of supported browsers, see Supported Browsers.
If you are planning to use users and groups for access control, and you do not have an Sun Java System Directory Server installed, install it from the Companion CD included with your Sun Java System Web Server software.
Install and configure Sun Java System Web Server.