http://static.howstuffworks.com/gif/invisibility-cloak-15.jpgOkay at the moment this technology is in it's infancy and for the above coat to work the observer has to be in a prearranged location and not move....however you can see where this technology may one day lead.....PREDATOR!!
This coat projects what is behind the wearer in front of them so that they partially appear to disappear. However, in theory there are alternatives ways which are far more effective at making something invisible.
If you can find a material which prevents light from scattering, you could coat whatever you wanted to make invisible in that material and it would seem to vanish into thin air!
Obviously this is incredibly complicated as the material would need to resonate at the same frequency as the light striking it to work.
I hope no one gives the CIA cloaking devices!!