Google Play v Apple iTunes
Price of Apps
iTunes also provides a wider variety of free apps.
Layout on Mobile Devices
Who Has More Apps?
Approval Process for Each Market
After submitting an app to Apple it could take weeks to receive feedback on your app. If it is rejected from the market, they will send it back with feedback as to what is wrong with it and how to get it approved. Apple also made it impossible to get an app approved if it's only purpose is to use location services to advertise to users. Apple will also reject apps that have too many bugs. Generally it takes over $99 to submit an app to Apple.
Once you create an app the first step is to register as a developer. Once you register, Google requires you to pay a registration fee at $25 to cut down on spam in the Android Market. Once you pay you have to agree to the terms and service agreement and file to the Android Market Servers. You're also required to send a high resolution app icon and two screenshots of your app. Once you've completed these steps you submit your app where users can search for it.