The whole jib thing (see other topic) got me thinking how the hell would I control the camera about 5m away from me. Obviously an Electronic ViewFinder with remote control of the camera would be ideal, but that's a VERY expensive solution!
So I had a rummage about on that Google and found it's possible to buy a £5 cable that uses a protocol called USB-on-the-go (hadn't heard of that before yesterday) - it turns intelligent devices that would normally be a USB client into a USB host.
So you connect the USB cable to your Android phone and then connect the camera's USB connector to the cable attached to the phone. Once you've got the cable, download DSLR Dashboard for free, connect everything up and hit the Liveview button on your camera. At this point the screen on my Samsung Galaxy SII burst into life. It was a touch laggy (I'm being picky) but showed Liveview in real time. It also gave control of virtually all of the variables for shooting and allowed shutter release, as well as start/stop of video...... in addition to that (and this is the bit that blew me away) you can step the focus whilst recording video.
This should work with most Canon DSLRs - certainly those with Liveview.
It's not often buying a £5 bit of tech wows me, but this really has blown me away with what I can now do with it. I understand the tech also works with Nikon gear, but can't validate that.
Dunno if there's anything for you Apple fanbois, doubt it as iOS7 seems to have obsoleted most third party cables
. doesn't really matter to me.