I want 2 ask how to upgrade my samsung i300x OS to WM5 or WM6?

It depends, Your provider usually makes the upgrades available if they have been officially released by Microsoft, in the case of the i300x, I do not think there was an "official" release so the other option is to find an updated ROM online (xda developers web site is a good place to look), however using an unofficial ROM will void any warranty and require you to manually enter in all of your providers settings (for Voicemail, texts, data connections etc).