cingular has launched a music recognition service called MusicID with technology from Shazam Entertainment and Musicphone. It's available via text messaging or Java application

From their press release:

MusicID: Messaging Application

Cingular MusicID users simply dial #ID (#43) from their handset when they hear a song they want to identify. After holding
their phone up to the music source for a few seconds, they will receive a text
message with the name of the song and the artist, as well as information on
purchasing a ringtone of the identified song, if available. The cost to use
the MusicID messaging application is $.99 per ID.

For users of the messaging application, Cingular is currently promoting a
"buy two, get one free" offer until March 31. Additionally, after the third
purchase, users will be invited to sign up for unlimited IDs at $6.99 per
month.

MusicID: JAVA Application

Today, Cingular customers who have a Nokia 6682 can ID a song using the
JAVA version of MusicID -- an industry first. When customers download the JAVA
application, they simply select the "ID Song" option, hold their phone up to
the speaker and then wait a few seconds for the song to be identified. Once
the song is matched, users will see a color page with the name of the song and
artist, as well as album cover art.

In addition to providing users with a colorful, easy-to-navigate
interface, the JAVA-application links directly to the ringtone and graphics of
the matched song and/or artist. The application also intelligently recommends
content based on the song matched, providing a link for customers to
immediately purchase the content. Furthermore, the JAVA-version of MusicID
stores previous ID's, allowing users to retrieve the information whenever they
feel the need or use their ID list as future playlists. It also has an "easy
to use interface" for texting matched songs to other customers, which then
links those customers directly to the IDs and content, if available. The cost
for the JAVA version of MusicID is $6.99 per month for unlimited IDs.