One of the great things about the Amazon Appstore is that it gives away a different Android paid-for app for free every day, which means you often find great gems for your phone, provided you check in every day. Apple is now taking a similiar route, and is starting to give away one app on the iOS App Store and another on the Mac App Store for free every week.

For example, this week you can download Cut The Rope: Elements to your iPhone for free, and of course it is the number one downloaded app on the Appstore.

On the Mac App Store you can now find the brilliant Cobook app which enables super-easy address book changes, and syncs with social networks like Facebook and LinkedIn. The app quietly sits on your taskbar, and when you need to search for a specific contact’s details you just click on the cobook icon (or tap the hotkeys) and start typing the name or business name.

You can also easily add to or edit existing contacts, which will then be synced back with the Address Book app on your Mac. So if you use a service like iCloud or Google Contacts, the changes will reflect on your phone as well. Nifty.

Hopefully Apple will continue to offer this free app of the week idea – it is still not clear if the apps are run as promotions, or if Apple fits the bill for the developers. Either way, it gives tremendous exposure to the developers if your App is deemed good enough by Apple standards.

You can grab Cut the Rope Elements here, and Cobook for Mac here.