...from:
http://www.apple.com/support/headphones/replacementprogram/

Apple Headphones with Remote Replacement Program

Apple has determined that the Apple Headphones with Remote included with the iPod shuffle (3rd gen) may fail under certain conditions. A very small percentage of iPod shuffle owners have experienced this issue.  These headphones were included with the iPod shuffle (3rd generation) made between approximately February 2009 and February 2010.  

If your headphones stop working or work intermittently as described below, Apple will replace them, free of charge, for two years from date of purchase.

Symptoms

  • Controls are non-responsive or work intermittently
  • Unexpected volume increase or decrease
  • Unexpected playing of voice feedback

Product Description

  • Apple Headphones with Remote - included with iPod shuffle (3rd generation).

Serial number ranges of the iPod shuffle with the covered headphones:
xx909xxxxxx to xx952xxxxxx
xx001xxxxxx to xx004xxxxxx

How to find the serial number on an iPod shuffle.

Note: Apple In-Ear Headphones with Remote and Mic and Apple Earphones with Remote and Mic which exhibit the symptoms noted above are also covered under this program.

All of these headphones have an in-line remote on the right earbud cable like the one illustrated here:

remote

If your headphones are experiencing any of the symptoms noted above, please use the Online Service Assistant on the Apple Support site to begin the replacement process. You will need to provide the following information:

  • Serial number of your iPod or iPhone
  • Shipping and Billing addresses
  • Credit card information

Please choose "Replace part or accessory" as the service needed. Then choose "Headphones" to complete the request.

Upon completion of your online service request, Apple will send you a replacement along with a pre-paid return envelope so that you can ship back the original headphones. It's important that you return the original headphones so that they can be examined and recycled responsibly. If Apple does not receive your original headphones within 10 business days, your credit card will be charged a non-return fee.

You may also visit an Apple Retail Store to obtain a replacement. We recommend you set up an appointment with aGenius. Outside the U.S., please visit an Apple Authorized Service Provider to obtain a replacement.

If you have any issues placing the replacement order, please contact Apple.

This worldwide Apple program does not extend the standard warranty coverage of the covered headphones.

Apple will continue to evaluate the repair data and will provide further updates to the program if needed.

Information as of 2010-04-16