Open Source iOS Add-ons
There are several open source iOS add-ons that I use and maybe there are some developers that do not know about them. Here's my listing:
* In-App Purchasing: Excellent blog post with source code to easily add In-App Purchasing to your app. The only thing that I have updated is to use the keychain and not NSUserDefaults. See Keychain Access below.
* Ask for Review: Add this to pop-up an alert after X-days or X-launches of your app and prompt the use for a review.
* Keychain Access: Add this to easily access (store and retrieve) data from the secure keychain. Use it in combination with In-App purchases for an increase in security.
* Mobile App-Sales: Use this to track your iTunes Sales info (jonkean's branch works now).
* Three20: I personally don't use it but many developers do.
I will keep this post updated as I find new ones too.