You can get the lastest source code for iPhly from my Subversion repository. You can use this command line:
$ svn co http://svn.lib.aero/iphly/trunk/ iphly
I distribute the software under a dual license. The source distribution is GPL. The binary distribution through Apple’s app store uses Apple’s standard EULA.
You can build an iPhly entirely from components you can buy at Radio Shack, and in fact I encourage you to. It may not look as slick as the factory injection molding, but it gives you the satsfaction of flying with your own transmitter. I bet you know very few people who build their own TXs.
The audio signal coming out of an iPhone is weaker than most modules can recognize. I use an LM324 OpAmp, available at Radio Shack, to boost the signal.
Futaba-style modules use a confusing pinout with power and ground on opposing pins (2 and 4). It is posible to plug a module backwards and burn it. I encourage you to verify which connection goes where before you turn the power on.
DIY Trainer Cord
Some transmitters expect “positive” PPM on their trainer input, where the signal is normally low and the pulses are high. In this case, all you need to connect an iPhone as the student input to your TX is a straight cable. Other transmitters, notably Futaba and Hitec units, expect “negative” PPM, where the signal is normaly high and the pulses are low. Below is a simple inverter I use with my Eclipse 7. All of the components fit inside the DIN-7 plug.