In the Fischer-Sozin Attack (6. Bc4 of course), where White plays 7. 0-0 and Black plays 7... Nxe4, White can obtain a clear advantage by playing the excellent 9. Bg5! move. It can be a little tricky--especially, without knowing the lines beforehand--but with accurate play you can win 100% of the time.
9...f6? does not work at all.
Post tactics from the Najdorf opening here. The most instructive tactics will probably be those that come from the early moves as opposed to those 40-60+ moves into the game (unless there is special feature from those endgames that is common to the Najdorf). Also, remember that explanations and/or lines will be useful, especially in an opening as complicated as this one.