:: What is Mod_rewrite
Mod_rewrite provides a powerful way to do URL manipulations and made more user friendly, by configuring rewrite rules, rather than modifying the webserver software.
:: How to enable mod_rewrite on apache
+ configure httpd.conf
Just setup / configure AllowOveride on your httpd.conf or vhost configuration like:

so configure httpd.conf / vhost configuration like this:

Add or setting vhost some like this:

+ restarting apache

+ Google
+ WebTutorial