This guide described how to install an iPhone AdHoc application to iPhone or iPod Touch through iTune that the application can be sent by email without using Apple's AppStore:
Step 1: Extract the zip file of the application to desktop, using unzip software like 7-zip or winzip. Also put the profile to desktop. The profile is used to identify that your iPhone is valided to install this application.
Step 2: Open iTune, you should able to find an item "Applications" in the "Library" on the left hand side of the iTune.
If you cannot find the "Applications", it may be hidden. Open menu item "Edit->Preferences..." and check the "Applications" in the prereferences dialog.
Step 3: Drag the application and drop to the iTune Windows
Step 4: Also drag the profile to the iTune Windows
Step 5: Connect your iPhone or iPod Touch to the computer, select the "Applications" Tab of your device, so should able to see the application is shown on the list, make sure this item is checked. and then click "Sync" at the bottom right. The application and the profile will sync to the device. You should able to see the application on your device after the sync synchronization.