By Prince McLean

Published: 12:00 PM EST

Making good on its promise, Apple on Tuesday unlocked a new feature of iTunes that allows iPhone owners to create their own custom ringtones, though an initial pool of compatible songs appears to be extremely limited.

The iTunes Ringtone Service

In announcing the service last week, Apple chief executive Steve Jobs said customers would initially be able to create custom ringtones from over 500,000 participating songs on the iTunes Store. An ensuing press release from the company, however, promised "over a million" songs.

Once you've purchased a participating song from iTunes, including previously purchased participating songs, it costs 99 cents to make up to a 30-second segment of that song into a ringtone and then sync it onto your iPhone.

Selection Limited

But when the service went live early Tuesday morning, tracks from many of the music industry's biggest names -- such as Dave Matthews, Jay-Z, U2, Black Eyed Peas and 50 Cent -- were not available for the ringtone feature. Albums from other artists were similarly fragmented in terms of which tracks could be used with the service.

For instance, a 14-track "Greatest Hits" album from punk rock band The Offspring revealed 10 songs that could be made into iPhone ringtones. However, the 4 omitted tracks comprised the group's most popular singles, including "Self Esteem" and "Come Out and Play."



How it Works

In order to use the ringtone service, you'll need the latest version of iTunes (7.4.1), which includes a ringtone column to indicate which tracks are available for conversion. Compatible songs will display a small ringtone "bell" icon in the column, which you can then selected to begin the creation process.



Users who own an iPhone but don't immediate see the ringtone column under iTunes track listings may first need to manually enable the column through iTunes' "View Options" dialog located until the application's "View" menu. Users will also have to agree to Apple's Terms & Conditions for ringtone sales before proceeding.



Once you've found a compatible song and agreed to Apple's terms, the process of creating the ringtone is relatively painless. iTunes displays a ringtone editor containing the source of the selected track where you can then select between a 3 second and 30 second sample to make into the ringtone.



Options to fade the beginning and end of the clip are available, as is a drop down menu to select the duration of the gap between loops. iTunes will also recommend that you preview your selecting before confirming your purchase.



Purchased ringtones will appear under a new "Ringtones" playlist in your iTunes library, as well as under a new "Ringtone" tab that displays in iTunes when your iPhone is docked and selected in the application's list of connected devices. The next time your iPhone syncs with iTunes, the purchased ringtones will appear in alphabetical order under the handset's ringtone selector, which is located under the "Sounds" preference.