mounting a local directory over another directory

[Micha Feigin <michf@post.tau.ac.il>]

Sorry for what probably sounds like a wierd question.

Is it possible to mount a local directory over another local directory 
(and not through nfs ?). It will save me a lot of looping around if its 
possible (I seem to recall seeing an option for this somewhere but not 
sure about it and I can't find it).

Thanks