iPhone app promo codes are used to provide free copies of an app to reviewers or other key users. The folks over at TapTapTap posted a great tidbit for sharing iPhone app promo codes in a much easier to redeem fashion. Rather than a user having to navigate inside iTunes or try to find the nicely hidden 'redeem' link on the iPhone, the end user can click a URL which will launch iTunes on a desktop computer or an iPhone directly from an email and start the redeem process.

The magic is in the URL you paste into the message:

https://phobos.apple.com/WebObjects/MZFinance.woa/wa/freeProductCodeWiza...

Copy and paste the above link and replace the end portion with the promo code. What could be simpler?