What is Ad Hoc Distribution?
Ad Hoc Distribution allows you to try an application before it’s available in the iTunes App Store. This is how we distribute iPhone applications to beta customers.
Preparation:
Before beginning the installation process you’ll need:

The .zip file for the application (usually AppName.app.AdHoc.zip)
The .mobileprovision file for the application (usually Ad_Hoc_Distribution_Profile.mobileprovision)
Your Device: the iPhone or [...]

In order to beta test iPhone applications, Apple has allowed for the release of these beta test applications onto individual iPhones & iPod Touches (henceforth referred to simply as iPhones). However, to do so, the developer has to have the iPhone’s UDID (unique device identifier) in order to install these “Ad-hoc” applications.
To find your iPhone’s [...]