The Apple iPhone 4 is undoubtedly one of the most popular smartphones the world has ever seen. It means that there're hundreds if not thousands of programs (apps) available to perform million of things – from identifying your location to sending vivid rays of light right through your iPhone 4 case. The best apps for your device are reviewed below.

One of the best iPhone 4 applications to date is Foursquare. It's software allowing you to roam your city and other places and then get recognized. This lets you get rewards for roaming around; besides, you are able to see where other people – for example, your friends – are roaming also. This software is location-based, awarding the user with a "mayorship" if he or she appears at specific places enough times. It's starting to become quite popular that information is emerging for instructing people using Foursquare on how to leverage their mayorships. Right now this application is being updated. And of course it has a very attractive price tag equal to zero – it's free.

The next program is for those users who can't keep up with everything they have to do within the day. They are strongly recommended to look into Evernote app for iPhone 4. All they need to remember for the start is to fit their gadget into iPhone 4 case, preferably the one that can be carried on the belt (not to forget the device in the first place), and install this app. It will magically broaden their thinking ability, as it's considered something like a digital way to keep mind on what the person is doing. The user is able to load up this program with images and notes, and synchronize them to any other computer. It'll help to memorize everything! If you have got any thought or a plan, all you need to do is to put it into Evernote app, which will keep track of the plan for you. This makes it incredible iPhone 4 free software that millions of people are already using.

Another piece of software is designed specially for music lovers. National Public Radio creates a program allowing you view all of the categories of their music lineup. This software will help deliver your favorite music style – from hip-hop to blues. Besides, there's not only music, but also live performances, interviews and unreleased songs. This one gets updated every day and it costs again nothing.

Here come the businessmen. There's an iPhone 4 app that takes care of the professional side of life. The program is called LinkedIn, and is similar to the one you might know in the Internet at LinkedIn.com. This software allows you to connect to almost a hundred million various professional contacts. The perfect point to start your business contacts, isn't it? Your network will see the update of your profile with LinkedIn each time you do that, and backward. This program has been redesigned not so long ago in order to make it more convenient to track the common features you have with the others on its network. The app comes in 8 different languages and the price is again nothing.

The last of the apps reviewed here is literally beautiful. Its name is Spawn Glow and it uses bright rays of light, clearly visible even though the protective film of the iPhone 4 cover. The user is able to manipulate them on the iPhone display to create their own personal light show. The rays of light flow and form in various colors and shapes, exploding on the screen with a mere double tap of the finger. Such Spawn Glow creations can be saved and uploaded to social networks, for example. In addition, the best light creations will be used on the Apple iTunes website. The program is free as the rest described.

All of those free iPhone 4 programs are currently available online, and more of them are being created weekly.