One of those apps is Midomi. (which was free at launch).

Apps such as Midomi can help you find a song that you hear on radio, or playing in a bar or if you know the tune and can hum it out.

SoundHound is the newest entry in this ‘What’s that song iPhone app’. SoundHound is available as free version as well as a premium version.

SoundHound’s music recognition is blazing fast! It can recoginize a song in just 4 seconds. It doesn’t matter if it is playing on the radio, or if you sing or hum it.

The free version gives you 5 free IDs per month. Your history and bookmarks stay with you. You can get additional IDs as in-app upgrades or get unlimited ID’s with the premium version.

Here are a few more features in the SoundHound app

• In-app lyrics
• Fantastic music discovery
• Artist top songs with visual popularity
• Instant sharing over email, Facebook or Twitter.
• Pandora station links
• One tap purchase with iTunes
• Playback of your iPod tracks & playlists – with SoundHound lyrics
• Music browsing with bios, in-app YouTube videos, discography and tour dates
• Instant voice search to take you straight into any song or arttist

SoundHound stands out from other ‘what’s the song’ apps in working as a iPod app replacement. SoundHound can play your iPod tracks and playlists while giving you the lyrics. This is absolutely great!

With the iPhone OS 4.0 giving more access to iPod app, I am looking forward to making SoundHound my default music player.

A must have in any music-lover’s iPhone.

SoundHound for iPad is also available.

Screenshots

Rating: 4.5 stars out of 5 stars

Availability: App Store

Price: Free and $4.99

AirBand is an iPhone app from the Music service provider – MP3Tunes.com.

Mp3Tunes provides everyone a free 2GB locker account (or an ad-free paid premium account) where you can store your music and video files and access them anywhere you have an Internet connection.

On the iPhone, you can access your Mp3Tunes Locker files with the free AirBand iPhone app.

You can upload files to your MP3Tunes locker account in one of many ways

• Use the web interface to upload files
• Use LockerSync software to mass upload files from your desktop (like Dropbox again). You can also schedule syncs to run on certain intervals. It works on Windows, Mac and Linux.
• If you install the browser plugins, you can easily add music to your locker right from the pages you are browsing.
• Mp3tunes comes with an open API which means other apps can di into your locker to play your files. For ex. Amarok, PS3MusicPlayer, WiiTunes can access your locker and play your files.

AirBand iPhone App

The app is pretty simple and functional to use. You login with your MP3Tunes.com account and you will be presented with a few tabs.

• Artists
• Albums
• Playlists
• Settings

It is pretty straightforward and the player screen looks pretty neat to. I am not sure I like the volume dial even though it looks cool.

You can also set the audio streaming quality depending on your connection.

I just briefly tried this app with one song and it performed well on 3G as well as EDGE connection.

With Apple purchasing Lala and the popular opinion that we will have our iTunes in the cloud, Airband could give that ability right now to take your music in the Cloud with you.

With the free 2GB Mp3Tunes account, you can free up your Dropbox account from music. I know I did!

Screenshots

Rating: 4 out of 5 stars

Availability: App Store [iTunes link]

Price: Free

With Midomi iPhone App, you can sing, hum or whistle that tune and Midomi will search for that music and return all the information about that song! It is available as a free iPhone App in AppStore.

Midomi works by hosting a recording studio where anyone can contribute by singing and adding to their growing collection of music database. And the next time someone searches for a song you sang, your result might be the top one!

Midomi iPhone App lets you hum, sing or whistle a song to find it. Once it finds it, you can either listen to the song or buy it from iTunes or watch YouTube videos if it’s available. Also, if you are at work and rather type the name of the song or part of it, you could do that too.

You might wonder what if I wanted to find out that song that’s playing in the background in the movie? Just put Midomi in grab mode and just put your phone by the speaker, Midomi will find that too. It’s your personal music assistant.

The technology behind Midomi is truly amazing as it doesn’t even care about language or tempo of the song. It uses special signatures to identify music. We are just scratching the surface with it and having lots of fun discovering music and other Midomi users.

Have a go at this cool iPhone Music App and let us know how you like it.

Update: As a couple of our readers have noted in the comments, Midomi has since moved from free to $4.99 in the App Store we just didn’t realize it.

Rating: 4 out of 5 stars

Availability: App Store

Price: $4.99