what is mod_rewite and how to use it?

[jadelinna]

Hi, I'm a freshman in PHP and please excuse my "noobiness". But what exactly is mod_rewrite? And how do i write it into my coding?

 

I'm currently involved in making a simple login/blogging script that is taking me forever to figure out how to code and where to continue. I have seen many graphic/layout sites that have URLs that are http://blah.com/blah/blah instead of http://blah.com/index.php?blah=blah

 

How do i use this mod-rewrite thing and where do I paste this? ???