5. Shazam
More music. More music. More music. Already considered an industry standard, Shazam fully integrates with the iPhone’s native environment, allowing you to seamlessly discover, buy and share tunes simply by holding your iPhone to music for just a few seconds.
Key user features:
- Tag music: identify music anywhere - whether it’s on the radio, TV, in a movie or in a store.
- Build your own soundtrack: instantly create your favorite playlist.
- Get the music: go straight to iTunes to preview and buy.
- Music Videos: see related videos of the track on YouTube.
- Capture the moment: personalize the tag by taking a photo and adding it to ‘My Tags’.
- Share the moment: send track details to friends via integrated email.
The latest version of Shazam is available for free and can be downloaded from Apple’s App Store on iPhone or at iTunes in the following countries: Austria, Belgium, Canada, Switzerland, Germany, Denmark, Spain, Finland, France, Greece, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Sweden, United Kingdom, United States, Australia, New Zealand.
4. Yelp!

Yelp.com is a data-intensive site bulging with user opinions and social-networking features. The iPhone app was clearly never intended as a replacement, but as a companion for the lost or weary to seek out a craft store, animal shop or grab bite to eat. That much is evident by the read-only quality, mobile-specific mapping and call functions, and the de-emphasis on social networking.
3. Pandora

Pandora Radio is your own FREE personalized radio now available to stream music on your iPhone. Just start with the name of one of your favorite artists, songs or classical composers and Pandora will create a “station” that plays their music and more music like it.”
Gone is the walkman. No need to lament the death of your favorite tunes though. Create your own radio station with Pandora. The 3G iPhone benefits from this app more than previous generations, as the music can stream faster, so there’s little to no down time between tunes.
2. Wordpress for iPhone
Wordpress has redefined blogging on the Internet so why not redefine mobile blogging? The fact that you can snap pictures where ever you are and enter them into your posts right from your phone is more than a little impressive. Start with only a few sentences or write a full novel, there’s no post-limitations from the iPhone version to what you would get on your normal PC web-based version.
1. Facebook
Facebook is a key player in the game of life now. It has become the epicenter of mobile life and the Facebook app for iPhone gets you connected on the spot. The app fully integrates with your current Facebook account where you can see your wall, post on others walls, take pictures and immediately upload them to your Facebook’s “Mobile Uploads” gallery and best yet, can even use the Facebook’s “Chat Room” right from your phone and talk to your friends in real-time.They’ve already had a version update that added a bunch of features to the already feature rich application and undoubtedly is the best looking / coded / functioning and practical application available. A solid choice for #1.