From ps3hax.net:
[QUOTE]
StreetskaterFU has found a method to run BluRay games from the PS3 HDD. Now before everyone gets excited and yells "ISO LOADER", this method only works with older gamers (with older update codes). The games currently confirmed to be working this method are Warhawk, MotorStorm, RFOM, GT5, COD3. (The legitimacy of this has been confirmed by Mathieulh)

There are two methods to do this, the legal and non legal way. The legal way requires (The legal way requiring the original disc, the non legal requires the game dump and any PS3 bluray game but two same size HDD's).

The video below demonstrates the non-PKG version of Warhawk being ran with Motostorm being "the proxy disc".