Apple have announced that iTunes users can now gift apps to each other. Previously iTunes user could only gift songs to each other. To gift an app to your friend you cannot use iTunes cards or gift certificates, only credit card would be accepted for payment of the gift app. Another important thing is that you can only exchange gift app to the person from your own county only.
To send an app as a gift to your friend, sign in to your iTunes and accept the new terms and condition. Then chose any apps, click on Buy App and then select Gift This App as shown in the screenshot above.