Apple have released RAW Compatibility Update 3.6 for Aperture 3 and iPhoto 11. Digital camera RAW formats retain more image information than JPEGs and can produce better results when used with imaging applications such as Aperture and iPhoto.
Mac OS X v10.6 Snow Leopard provides system-level support for digital camera RAW formats from the following cameras:
Supported by Digital Camera RAW Compatibility Update 3.6
Canon EOS Rebel T3 / 1100D / Kiss X50
Canon EOS Rebel T3i / 600D / Kiss X5
Panasonic Lumix DMC-FZ100