If you’re in a car and hear a new song come on the radio, you no longer have to wait until home to buy the song. Just whip out your iPhone, and as long as there’s a 3G or EDGE signal, you can purchase and download the song directly to the iPhone. Here are instructions on how to do this. You’ll need an iTunes account, and you’ll also need to remember your password.
1. Tap on the iTunes Music Store icon.

2. Search for the song by selecting the Search tab at the bottom, or browse through the featured songs and artists or the Top Ten lists.

3. You can listen to 30 seconds of the song for free by tapping on the song name.

4. To purchase the song, tap on the button displaying the price. It will turn green and display the words Buy now. Tap the green Buy now button.

5. A prompt asking for your password will pop up. Enter your password.

6. Tap the Download tab at the bottom right if you want to watch the song download.

And that’s it, you’ve download the music to your iPhone. To listen, tap the Purchased button, or launch the iPod app.
Questions and Notes:
How do I copy the songs from the iPhone to my computer?
The songs will be copied onto your computer the next time you connect and synch the iPhone.
Can I redeem iTunes Gift Certificates using just my iPhone?
Yes. Tap the Downloads tab, then tap the Redeem button at the top left of the screen.
Is there a size limit for downloads?
If you’re downloading over 3G or EDGE, each individual song can’t be more than 10 mb in size. Most songs are around 3-5 mb in size, but some larger rock epics may not download unless you’re on a WiFi network. If you can’t download the song on the iPhone, you can download it using your computer at home without paying for it twice.