Source: Xbox Originals Achievements On The Way
A supposed Microsoft Source has tipped off Europe-Nintendo (why a Nintendo site?) that starting in Sping 2009, starting with Halo: Combat Evolved and Fable, the Xbox Originals catalog will be patched to include achievements into the entire back-catalog by Winter 2009. Each game will have a total of 500 achievement points, according to the source.
According to the source, Microsoft has stated this maneuver was taken to increase gamers’ interests in Xbox Originals downloads. We can only wait for confirmation.
Source: Achievements to be patched into original Xbox titles [Europe-Nintendo]