Apple's photography software now can accommodate raw images from some newer digital cameras through the release of Digital Camera Raw Compatibility Update 2.3.
Specifically, the update to iPhoto '08 and Aperture 2 means that the photography software can deal with raw images from three prominent new digital SLR (single-lens reflex) cameras: Canon's midrange EOS 50D, Nikon's video-enabled midrange D90, and Sony's ambitious 24-megapixel full-frame Alpha DSLR-A900.
Also supported is Nikon's high-end compact camera, the Coolpix P6000.
Raw images are taken directly from higher-end cameras with no in-camera processing into a JPEG. That means photographers get more flexibility when it comes to exposure, white balance, sharpening, and other options, but also that photos require manual processing.
For software companies, supporting raw formats requires either that they have to figure out a host of proprietary raw formats, because each camera model has its own, or rely on the manufacturers themselves to support release codecs supporting the cameras. Adobe Systems and Apple take the former route; Microsoft takes the latter.
To check if your camera is supported, see Apple's list of raw-format camera support. Adobe's raw-support list is a little longer, including support for Pentax's newest entry-level model, the K2000, the esoteric Fujifilm FinePix IS Pro, and Olympus' latest ultrazoom, the SP-565 UZ.