Camera Labs has a very nice Camera Labs D-SLR dust workshop. The technique they use at Camera Labs involves preventative practices keeping the camera switched off, holding the camera upside down when changing lenses, using a body cap when there's no lens on the camera, and making sure that any lenses are dust free before they go on the camera. They also use blower brushes to clean the lenses from time to time, holding the camera upside-down.
