I recently came across this great podcast Missionary Talks, where David Peach interviews missionaries and they talk together about their experiences overseas.
From the blog:
Missionary Talks has a three-fold purpose. Primarily it will help young people, and those considering missions, realize that missionaries are normal people fulfilling God’s will in their lives. It will also be a help to those church members who support missionaries know better how to pray for the men and women on the field. Finally, it is to be an encouragement to other missionaries as they learn about other fields of service and how God is working around the world.
I have just started listening and it has become a great addition to my podcast list. Just over a year old, podcasts are uploaded weekly and can be listed to through any mp3 player or even straight from your computer! I personally find it interesting to hear about what God is doing around the world and the short stories of His workers! Each show is about 15 minutes long.
He also has a little section about unreached people groups on the right side column.
You can listen to a short introduction audio here (clicking the link will open a mp3).