Make iTunes Previews your iPhone’s custom ringtone

Did you know that iTunes offers short audio samples or previews of its entire library as free downloads? I am talking about those 30 second clips of every song on iTunes that you can listen to before you buy. That makes these iTunes previews perfect ringtones as a ringtone is usually nothing but a tiny snippet of a song and not the entire song.
The good news for iPhone users is that an iPhone hack can help you download these audio previews from iTunes and install them onto your iPhone as custom ringtones.

I was not aware that iTunes freely offers these short audio previews of its entire library. It might not have been a big deal until now, however as mentioned earlier an iPhone hack will help you use audio previews as custom ringtones on your iPhone.
Thanks to the folks at Tuaw below are the steps that you need to follow to make this work:

"1. Create a new playlist: Drag unpurchased songs from the iTunes store into your playlist. The songs will retain their "Add Song" buttons and their price within the playlist.
2. Export your playlist: Select the playlist in the sources column. Control-click/Right-click the playlist name and choose Export Song List from the pop-up menu.
3. Save the playlist as plain text: Select Plain Text from the Format pop-up and save the playlist file to your desktop.
4. Open the playlist file: It is a tab-delimited file of columns, so you can open it up in Excel (my preference, make sure to option-drag the text file onto the Excel icon) or a text editor like TextEdit.
5. Locate the file URLs: Each file URL appears in the final Location column for each line. Copy the URL.
6. Download the files: In Safari 3.0, open the Downloads window (Windows->Downloads). Paste the URL into the Download window and allow the file to transfer. Your computer must be authorized to your iTunes account. You may want to try playing back the file in QuickTime Player just to be sure it downloaded correctly. If you're not a Safari 3.0 user, use your favorite alternate such as curl, wget, or so forth.
7. Rename: Give the file a more meaningful name than, for example, "mzi.rwgtaash.aac.p.m4p". Retain the .m4p extension.
8. Upload to the iPhone: Use your favorite method (iphoneinterface, sshfs, sftp, whatever) to copy the file to /Library/Ringtones on your iPhone.
9. Select the ringtone: On the iPhone, navigate to Settings -> Sound > Ringtone and select the new file. The ringtone will play back as you select it."

Folks at Tuaw are also reporting that some newer music releases do not work as ringtones and have not been able to figure out the reason. But you still have zillions of songs to choose from so you shouldn't be complaining. Enjoy!!