External viewfinder

bonje wrote:
I would like to use a laptop as an external viewfinder for the IXUS
700 and the EOS 5D Mark II through the USB cable. Is there any
solution around?

The Ixus 700 has an AV-out port (see halfway down the page
http://www.dpreview.com/reviews/canonsd500/page2.asp).
The EOS 5D M2 has both HDMI and AV out ports (see the bottom of this
page http://www.dpreview.com/previews/canoneos5dmarkii/page6.asp)

Both cameras have a video-out or av port, so this output could be
displayed on a TV screen of any size you desire.
The only wrinkle with the EOS 5D M2 is that it has to be put into
live-view mode, otherwise something like a Zigview
http://www.zigview.co.uk/ would have to be attached to the viewfinder
eyepiece.

If you want to edit or otherwise process the video stream produced from
these cameras a video capture device that plugs into a USB or FireWire
port on your laptop would be required.
Something like this, maybe:
http://www.pittjug.org/catalog/joysticks_and_game_controllers/2/usb_video_capture_77.html