I believe that in certain regions google does not allow market to be used.
This is dependent on where the device is purchased.
Android Market was removed per requirements of Google in the individual Arabic regions such as UAE, Egypt, Oman and Saudi Arabia.
If you have a phone without this app it likely came from one of these regions.
There's an alternative app store I've used called SlideMe.. must download from http://SlideME.org/sam2.apk
..you can find the main website at http://slideme.org
.. once installed.. it will show you all apps in market regardless of your phone's model. It will also tell you if the App is compatible with your phone as well. Make sure to in-able: "allow install of non-market applications" in "Settings" under "Applications". Note: it works a little different then the Android market (it doesn't auto-install after downloading).. click on an app to download.. then once downloaded.. slide down the top task-bar on your phone.. then click on downloaded app to choose to install.