I found Martin's page. You can download a small excerpt from a commercial and a narrative.

http://www.hobsons-international.com/voices/647/martin_freeman

He also narrated a program called Backstairs Billy - The Queen Mother's Butler on Channel 4.

On the PBS Sherlock website, Benedict is asked about his favorite moments as Sherlock, but Benedict spends most of that time talking about Martin ( Read more... )