Hi David;

PCM File Requirements for Custom Ring Types

The PCM files for the rings must meet the following requirements for proper playback on Cisco Unified IP Phones:

•Raw PCM (no header)

•8000 samples per second

•8 bits per sample

•uLaw compression

•Maximum ring size-16080 samples

•Minimum ring size-240 samples

•Number of samples in the ring is evenly divisible by 240.

•Ring starts and ends at the zero crossing.

•To create PCM files for custom phone rings, you can use any standard audio editing packages that support these file format requirements.

http://www.cisco.com/en/US/products/hw/phones/ps379/products_administration_guide_chapter09186a0080799741.html#wp1088056

Check here for free shareware;

http://www.freedownloadscenter.com/Best/pcm-audio-file.html

Hope this helps!

Rob