Different versions: http://www.modaco.com/content/i9x0-omnia-http-omnia-modaco-com/299750/windows-6-5-i900-chefs-list/
Regarding the installation, follow this steps:
Prerequisites: Before you do that you need to install Samsung modem and active sync ..... and have Win XP on the computer, it's simpler on Win XP;
Actions: Unzip the archive / click or double click on the exe file / hang up the phone / connect phone to PC (data cable) / start phone / Click the Start button and expect "Job Done" message
(thanks to maja_ro).
Have fun! :)