You need to following components to run Inventory:

A working Web server
Any web server that can run PHP is okay. We recommend Apache (1.3.x or better) or IIS (4.x or better).
PHP 4.x or better (working properly on the above web server)
You can get PHP at PHP Website. (If you're using Linux some have pre-built PHP packages you can install.). Make sure that your PHP installation works properly on your web server, and that it has the MySQL extension installed.
Inventory works best with the register_globals setting set to "on" in php.ini (you can set it globaly or just for the directory where Inventory is installed.) From version 0.81 this setting is no longer mandatory.
MySQL 4.0.14 or better
You can get MySQL from their website.
Modern Browser
Inventory requires a browser which supports CSS, Javascript and cookies.
It has been developed and tested on Mozilla Firefox 1.0 and Microsoft Internet Explorer.
Make sure that Javascript and Cookies are allowed (at least for the site running Inventory).