The apache module mod_rewrite is compiled by default into the SW-Soft Linux Apache installations. You can see this by the following line in the Apache configuration file in /etc/httpd/conf/httpd.conf :
LoadModule rewrite_module modules/mod_rewrite.so
By default the rewrite engine is off. You can turn the rewrite engine on by placing the following command in a .htaccess file that you place in the root directory for your site:
RewriteEngine On
You then can place the rewrite rules you wish to add for the site in the same .htaccess file.
You can find Apache 1.3 information on mod_rewrite at http://httpd.apache.org/docs/1.3/mod/mod_rewrite.html.
You can find Apache 2.0 information on mod_rewrite at http://httpd.apache.org/docs/2.0/mod/mod_rewrite.html.