The DSLR Remote  is a wireless cable release for your Canon EOS DSLR camera. onOne’s DSLR Remote for the iPhone enables you to control selected parts of your DSLR camera when the camera is connected to your computer.  The DSLR Remote server application can not only transfer commands sent by the iPhone / iPod Touch to the camera, but allows the captured image to be viewed on the handheld device. Connecting to a laptop over Wi-Fi, the software can obviously take shots at will, but it can also control settings including shutter speed, aperture and white balance.
Supported camera bodies include the consumer-oriented Canon EOS Digital Rebel XT, XTi, XS and XSi, the mid-range EOS 20D, 30D, 40D, 50D, 5D, and 5D Mark II, the professional EOS-1D Mark II, Mark IIn, and Mark III, and finally the EOS-1Ds Mark II and Mark III.
There’ll be two versions available: Professional, for an introductory price of $9.99, which allows you to control a host of camera settings, and the $1.99 Lite, which simply lets you fire the shutter.
