Picturing the Century is an online photo exhibit created by and hosted by the National Archives and Records Administration. The exhibit contains six galleries of images from 20th Century life in the United States. NARA provides teachers with six lesson plans including a printable worksheet for using the Picturing the Century images in their classrooms.

Applications for Education
The lesson plans provided by NARA to accompany Picturing the Century are written in a manner that they can be adapted for use in classrooms from elementary school through high school.

Here are some related resources that may be of interest to you:
Lesson Plans and More for US History Teachers
Lesson Plans from the US Department of State
The Farm Letters – Stories of Great Depression Life