Some internet websites that can help with learning or teaching English. All are free
http://www.starfall.com/
http://www.mingoville.com
http://www.learn-english-online.org/
Esl Partyland I received an email suggesting I add this site from Brooke. Her student Abby recommended it.
http://www.5minuteenglish.com/ Another email suggestion; this one was from Lily whose student Ashley recommended it.
More advanced:
http://www.englishpage.com/grammar/
A website I have used a lot is abcteach.com. It is a subscription service, but I have found it worth every dollar ($35) and then some.