Apple has introduced so many new features in iOS 4 that it has not been easy to keep track of all these cool new additions (especially the minor ones). 

While most of you must have gotten used to new features like FaceTime (for iPhone 4) and iBooks on the iPhone, there are little tricks that make these apps all the more useful and exciting.

David Pogue at the New York Times has provided details about few features in iOS 4 that you may find useful. 

Unified Contacts Listing

The earlier versions of the iOS had a tendency to display the names of certain contacts multiple times especially if you were connected to them independently on MobileMe and on the Corporate mail account. The new Contacts app unifies these details so that the names on the 'All Contacts' page appear only once. These listings unify contact names from your iPhone address book, MobileMe account and your corporate exchange server so that you may access all information about your contact from a single page. To access any particular contact card, you simply have to scroll down to the bottom of the contacts page and tap on the Linked Cards section. 

Of course, since this is automated, the listing is prone to errors and hence the unified contacts listing page also lets users to unlink certain cards if you think they were wrongly linked. Additionally, users may also insert new contacts to a unified card by tapping on Edit -> Link Contact and choosing a contact name to link. This is especially useful if you want to group a list of users under one head.

FaceTime Tricks:

• Camera Toggle

This is something you may have already come across if you regularly use FaceTime. Nevertheless, it is too important a feature to miss. As you know, the FaceTime video calling feature requires a front-facing camera to work and hence is not supported on older iPhone models. Nevertheless, if you do own an iPhone 4, it is still possible to use the rear facing camera instead of the front camera for video calling. To do this, you simply have to tap on the camera-rotation icon on your FaceTime screen to toggle between the two cameras. 

• Mute Audio/Video On FaceTime

There are times when you may need to mute just the video or audio while a video calling session is on. The audio-mute option is pretty straightforward. Users need to tap on the microphone icon on the application screen to mute the audio. To mute the video instead, simply move away from the FaceTime screen to any other program or just press the Home button. This will display a blank screen on the other end even though the FaceTime session is still on and the person at the other end can hear you.

VoiceOver For iBooks

It is possible to turn your iBooks into audiobooks that will read out the passages for you. To get started, you will first need to enable the VoiceOver function by navigating to Settings -> General -> Accessibility and enabling VoiceOver. Do note that turning this feature on will now require you to double tap on options to select since the first tap shall primarily read out the option for you and you need to use three fingers on the screen to scroll. 

Once done, launch the book to read then tap on the first line of the passage and swipe down to the bottom of the page with two fingers. This will prompt ibooks to read out the book for you. The option will also automatically turn pages and you can stop the audio by tapping on the screen with two fingers.

Hope you enjoyed these tricks. Have you come across any other cool hidden features in iOS 4? Do let us know in the comments below. 

[via The New York Times]