make money designing smartphone apps in your spare time. With the right tools, designing smartphone apps is fairly easy. First, you will have to decide which smartphone platform is best for your app, and then write the code. Or, at least have someone on your team that knows how to program code do it for you.
Designing and creating the user interface for your smartphone app is something that you should learn more about. A good place to start for the Apple iOS platform is the iOS Dev Center. If you decide to create an app for the Android platform, check out the Developers Guide For Android. Also, take a look at Windows Mobile Development Center and the BlackBerry Developer Zone, if you want to use those platforms for your smartphone app.
Another thing that I suggest you do is read the latest books about developing smartphone applications. Check out your local library for these types of books, or purchase them from popular book retailers, such as Amazon, Barnes and Noble, etc. Invest a few dollars in a good app design starter kit, like the Premium PSD Software Kit. Web developers are raving about the software, because it includes some amazing graphics, various types of designs, and elements that you will need to create a cool-looking user interface for your app. Be sure to check out the websites, App Makr and Buzztouch. You can use both of these sites for free, to learn how to design and build smartphone apps online.