Another good place to get videos on this topic is "PBS Evolution". They have a series of 7 videos that break down the topics of evolution. I didn't show all 7 videos to my 7th grade class, but I did show the last video about the topic being controversial. Above all else, when introducing this topic please tell the students to go home and talk with their parents/guardians about their beliefs. If you do this prior you will have more open conversations in class and not stepping on family's beliefs.
It is hard to find a video that stands the middle ground of evolution. This IS a concepts that has to be taught in Virginia schools, so I try to stay with evolution in regards to animals and not humans. This video talks about Darwin and natural selection and also hits on other vocabulary that will be on the SOL tests. If you find another middle of the ground video please post here.