Both my iPhone 4S and Nexus 4 mount perfectly. Next up is the Triggertrap mobile dongle, this when then allow me to connect my iPhone or Nexus 4 to my Canon T4i and use the Triggertrap app to control the camera for shooting time lapse. The phone will mount on top of the camera. You have to have both cables, the Triggertrap kit linked below has both cables, 1 that goes to the phone and the other that goes to the camera. The 2 cables will then connect to each other.
I should have my Triggertrap dongle by Friday, once I get it I will do a full review.
The Triggertrap dongle is $30 from Amazon: http://amzn.to/11iGyfg
Free to download, Triggertrap for iOS: http://goo.gl/vsv4P
Triggertrap for Android: http://goo.gl/Zb4Rh
Triggertrap for iOS is iPhone only but works in 2x mode on the iPad. I currently don't have a way to mount my big ol' iPad to my camera though so the iPhone or Nexus 4 will suffice.
I am using the Case Star to mount the phone to the tripod. It works with my iPhone and my Nexus 4. I think the Nexus is about as wide as the mount will go though.
$4.99 on Amazon: http://amzn.to/113lryP
More info: http://www.crizzo.net/2013/04/case-star-smartphone-tripod-mount-holder.html