I purchased a wft-e5a for my eos 7d and have been testing it out. The wft (wireless file transfer) mode Appeared to have promise but is not the killer app i've been looking for. Though it does create a web server that can view the live viewm output and does have focus control it does not allow zooming in to accurately check focus like the EOS utility does. So while I can connect to it from an iPhone or iPad and take images and copy them to the devices the lack of zoom for focus limits the use ability.
Information on the wireless file transmitters is spotty and Canon's lack of on-line manuals is perplexing but a fairly decent article on the modes is available on the CPN Europe site[/u]
The EOS utility mode works really well both wired and wireless in infrastructure and ad-hoc modes but still requires a laptop to run the software and the same functionality can be obtained without spending the $ on a wft just by tethering with a USB cable.
There is a software development kit for the canon dslrs so perhaps some day some one will create an app to either tether from a tablet or use a wireless connection to allow using a larger screen to see the live view images and zoom in to get critical focus.
Back to using the angle finder ...