Even with the huge number of mobile apps already available, cellphone screens are always awaiting new ideas from innovative developers. If you have your own idea for the perfect app, whether for a wide audience or just your own use, you're in luck—you no longer need to be a deft programmer to produce it. There are now a number of app-generating tools on the Web that will enable you to bring your concept to life by clicking instead of coding. You may have even downloaded some of the resulting mobile apps already, like Inside Trader, a strategy game built with a tool called PhoneGap, or the Spinal Tap iPhone app, made at MobileRoadie.com. The best app-building option will depend on your price range, the platform you prefer (iPhone, BlackBerry or Android) and the functions you want. Some will even navigate the processing of submitting the app for you. Here's a guide to help you choose the right tool.