Before I go the easy route, there are some standard (fairly nerdy) ways to create apps. It starts with a SDK or Software Development Kit that you download from either Apple or Android. There are different processes involved for developing and getting your app in the respective store. If you like a challenge, want to learn how to code and feel a super sense of accomplishment, definitely check out these.
Now, I am lacking on my computer programming skills so I turn to those that have streamlined the process. There are lots of sites now that make the development process so easy, in some cases all you need is a web address and in about 30 seconds you create something to be proud of.
AppMakr-This is one of those "plug and chug" app makers. You start with a URL and from there you can customize your app with the features you want. The cost is free but they place adds in your app. For $79.00 you get full control and get a whole bunch of other features to further customize your app. AppMakr only develops for iOS but still, a great introduction to the app building process.
iBuildApp-Another one of the easy app builders, there are lots of features to choose from. Adding tap-to-call, Youtube channels, maps, Twitter feeds and more, the interface is slick and easy for even the novice user to develop. You can build an app for iOS or Android, however there are some associated developer fees that you will want to check out.
Shoutem-Similar to the others, this has a few less features but when it comes time to publishing, you do save a little bit of money. Again, take your URL and in a few moments you have an app ready to publish. Create an app all at once for iOS and Android, give this one a try.
Android App Inventor-Created by Google, this is now a project for MIT that aims at helping anyone who wants to create an app do it for free. Development happens all in your browser. While it is a bit more tricky than the others, it is easy enough to get the hang of because it its drag and drop. There are whole list of buttons, actions, and objects you can drag to the screen to create an app that was designed truly by you. This one I see working great in a Computer Science class and kids could develop all kids of apps. All you need to get started is a Google account.
So you can get started right now and create an app for your school, your blog or, if you are feeling dangerous, design something from scratch. Do you have a favorite app designer or an app you designed with one? Leave a comment below.