The tool is free but you can also created an account.
Historica Canada - Education Portal
Vocaroo- Students record and listen to their voice online and listen. All ages and levels.
American English - From the US Dept. of State, provides resources prepared for and by English-teaching professionals. Includes both a teacher and student portal.
English Listening Language Lab Online- A free online listening resource of over 1,000 listening activities designed especially for ESL students. Most listening activities include images, an interactive quiz, transcript of the audio and downloadable MP3.
ESL Resources for Students – Online Writing Lab at Purdue
Visual Dictionaries: http://visual.merriam-webster.com/