I really don't know why it's so hard to find an answer to this, but can someone point me to a guide or something on how to create an iPhone app without Apple's SDK... for example like an app in Installer or Cydia.
On a side note, my objective is to dump NMEA GPS data over either WiFi, bluetooth, or the USB cable from my iPhone 3G. If I can't do NMEA, then perhaps coordinates will suffice.