That picture is from the first viking mission, and newer better cameras have taken better pictures, and most scientists believe it to be a mesa of no
particular interest.......However many remain unconvinced here is a site where you will find a resonable(IMO) view of the "face" being an actual
face.LINK
Faces appear in clouds and mountains ect., all the time. I think it's safe to say that the face on mars is just a play of light and shadows. Then
again some people think that this thingy is artificial.
I'm pretty sure that it's just a natural feature, however if your interested in some of the more far out theories here is a great site for those.
They have detailed numeralogical theories about the martian region "cydonia".
Anyway, old topic. It's a geologic feature. Try New and Improved Search
Function but also the [url=http://www.abovetopsecret.com/forum/89/pg1/srtpages]Space Exploration Forum[/url.