What is the purpose of a provisioning profile and why is it needed when developing an iPhone application? If I don\'t have a provisioning profile, what happens?
You need it to install development iPhone applications on development devices.
Here's how to create one, and the reference for this answer:
http://www.wikihow.com/Create-a-Provisioning-Profile-for-iPhone
Another link: http://iphone.timefold.com/provisioning.html
A Quote from : iPhone Developer Program (~8MB PDF)
A provisioning profile is a collection of digital entities that uniquely ties developers and devices to an authorized iPhone Development Team and enables a device to be used for testing. A Development Provisioning Profile must be installed on each device on which you wish to run your application code. Each Development Provisioning Profile will contain a set of iPhone Development Certificates, Unique Device Identifiers and an App ID. Devices specified within the provisioning profile can be used for testing only by those individuals whose iPhone Development Certificates are included in the profile. A single device can contain multiple provisioning profiles.
Apple cares about security and as you know it is not possible to install any application on a real iOS device. Apple has several legal ways to do it:
Development Provisioning Profile
allows you to do itDistribution Provisioning Profile
[About] and Apple after review reassign it by they own keyDevelopment Provisioning Profile
is stored on device and contains:
Xcode
by default take cares about