Some history: I was hired to work as a probational employee for an upcoming iPad app that was starting out. Since I hadn't written a single line of native iOS production code at that time, I had to scramble. I read Big Nerd Ranch's iOS Programming book front to back over a two week period on the bus and realized I could probably learn a lot better by building an app that I wanted to use.
I started tinkering last October, on and off the bus, never expecting to get very far and ended up polishing it and getting it fully ready last month. The rest of the time was spent building the website and ironing out other visual bugs.
Take a look if you'd like. There's a video showing off how it works on the website so you don't need to buy it :)
Show HN: I built a music app for iOS to learn how to build iOS apps
ffwdapp.com