When I started to consider going back to school to become a teacher, I spent nearly a year substitute teaching in a wide array of high school classrooms. It was mostly a very positive experience, but there were a few days when I felt like this substitute teacher, overwhelmed and frustrated. Usually, the root causes of those feelings was not the students' behavior. Rather the causes were a lack of clarity of direction in the plans the left behind by the classroom teacher and a lack of clarity in expectations for the students (and there were a few times when no plans were left at all). There are two resources that I wish teachers had available and had used when I was substitute teaching, Viddler and Drop.io. I use these now when I'm absent from my classroom.
Viddler is a free video hosting and sharing service. Viddler, like YouTube, allows you to record and post videos directly to the site through your webcam. I use Viddler and my webcam to record short videos in which I explain to my students my expectations for what they are to accomplish while I am out of the classroom. I post the video to my course blog. My written plan for the substitute always starts with "have students watch the new video on the course blog."
Drop.io is a free service that allows you to host and share files online. Drop.io also has a free podcast recording service called Phone.io. Using this service you can call into your Drop.io drop (Drop.io's term for a page), record your message, and have it appear as an MP3 on your Drop.io drop. Anyone visiting your Drop.io drop can listen to your recording. Drop.io also provides an embed code for your recording to put your recording on your blog or website.
Applications for Education
By using Viddler and Drop.io I can directly deliver my plans and expectations to my students even when I'm out of my classroom. Doing this eliminates the possibility of a student saying "the sub didn't tell us to do that." It also helps out the substitute teacher who now has a clearer idea of my plan for the day.
I'm in the fortunate position of working in a 1:1 school. If your school is not 1:1 you can still use Viddler and Drop.io. You just need one computer in your classroom that the substitute or your students can access when you're not in your classroom.