How can I fix waiting iPhone apps that will not install?
When an iPhone application has a grey icon and says it's waiting, normally the app will quickly change to loading and then installing as it continues the process of downloading and installing to your device. Sometimes the app hangs at waiting and never progresses. Usually this is due to a connection problem with the App Store or some other issue.
The easiest way to correct the problem is to restart your iPhone using the power button. When the iPhone reboots the waiting icons should continue to load and install normally, assuming your cellular data or Wi-Fi connection is working properly.