Educations (free) is both a website which requires a browser that supports flash, and an iOS app (no Android at this time, March 2014) Users record record their screen using it like an interactive whiteboard. This is one of the easiest ways to record tutorials from your screen and which you narrate, on your iOS device screen, save as a video and share. Built-into Educations is an option to search for education-friendly images online. Visit the "Showcased lessons" on their site or in the app to view examples for different content areas: math, social studies, science and ELA world languages, and art lessons created with this program. Requires iOS 5.0 or later.
ShowMe (free) is similar interactive whiteboard app with a companion ShowMe website. WIth the You can record your tutorial with imported images or draw and erase on the screen. A very easy app to use. Requires iOS 4.3. View examples on the ShowMe learn page - including CCSS aligned lessons..
Explain Everything ($) is one of the highest rated apps for creating screencasts (also available for Android OS.)
This interactive whiteboard has so many features - including the option to insert web pages. You can narrate, import and insert, draw and annotate, zoom and pan, and export files. You can import: photos, videos, pdf, ppt, doc, .xls, Keynote, Pages, and import from locations such as Dropbox, GDrive, Box, Email, iTunes and others. You can export your videos as mp4 movies, pdf documents, or png images.