Currently, there is no supported way of doing this
There used to be, in an early version of Xcode 4. Then Apple killed it - for reasons of being too buggy.
I, like you, often wish they would bring it back, just so that those that do use it don't have to use cables all the time.
Except for Ad Hoc
EDIT: I now understand the question better - you don't want to use the iPad for development as in debugger and whatnot. You want your friend to be able to run your apple on his device. Got it. Google iOS ad hoc