One way to see if mod_rewrite is installed is to create a file called info.php with the following contents
Put the file in your server root and view it at http://localhost/info.php. Go to the apache section and look at Loaded Modules. If you see mod_rewrite listed there, you can start using the mod_rewrite commands. If not, you have to play with the apache config file: http.conf, add the following (a website told me to do this):
... and make sure the mod_rewrite.so file is in the right place. Then restart your web server. (suse linux: "rcapache2 restart", or windows: Control Panel->Administrative Tools->Services, right click on Apache and select restart)
Apache fails to restart.
In windows you can discover the reason using the Event Viewer (Control Panel->Administrative Tools->Services->Event Viewer). It gives the error for Apache:
Invalid command 'AddModule', perhaps mis-spelled or defined by a module not included in the server configuration
AddModule for mod_rewrite is for apache 1.2 to 1.3x, but not apache2. I was running Apache2, so instead, the following worked for me in the apache config file:
Now restart apache, and check your http://localhost/info.php file and Voila! mod_rewrite is there, listed as a Loaded Module.
Now as for how to actually use mod_rewrite there are a lot of examples out there,
thats what google is for, right?