Help: developing iPhone apps

I'm currently learning C++ and I'm looking at also learning objective-C. I have a friend who is very good at designing (Photoshop). I am looking at making some pretty basic apps that just display helpful information. I'm not looking to make games or anything advanced. Some ideas are some sports apps that shows team stats, competition ladders and player profiles. And some apps for public transport and things like that. Yes I am aware that I will need to join the Apple Development Program and run Xcode and the SDK...

What should I be learning in order to make an app like I have mentioned? So the app will launch, it will come to a "home screen" and will have linked buttons to different pages within the app which will display the information. So for example you will click "teams" then you will have a list of the teams, then you click the team and you will be taken to the team page where you can view stats and more. And for the public transport apps it will be similar but I'll also have to intergrate a searching feature which will tell you what bus or train to catch to get to certain places and will have maps (preferably integrated with GoogleMaps)....

Well, if anyone has some advice for me, that would be great.

Thanks