We are now reading Missionary Stories with the Millers. It is wonderful! Another good book is You Can Change The World *Learning to Pray For People Around the World* by Jill Johnstone It has 26 countries from A-Z and 26 people groups. Each country has a map, info on the country, people, children, trade, food, and their religious beliefs. On the sidebars are prayers specifically for that country. There are two volumes. I think they are out of print, but you can find them on amazon, ebay,and some other sites. I highly recommend it if you can get one!
HTH!
Also, Voice Of The Martyrs has a great free kid’s magazine and website to pray for persecuted Christians. You can find info on http://www.kidsofcourage.com/?page_id=160
And the parent site http://www.persecution.com/actionpacks