Here are some links worth checking out if you are studying ‘Macbeth’:
Bitsize covers the basics
http://www.bbc.co.uk/schools/gcsebitesize/english_literature/dramamacbeth/
More basics from Sparknotes
http://www.sparknotes.com/shakespeare/macbeth
A clip about the character of Lady Macbeth
http://www.bbc.co.uk/learningzone/clips/macbeth-lady-macbeth-in-context/3041.html
Some challenging stuff from the RSC
http://www.rsc.org.uk/explore/macbeth/
More excellent work from the BBC
http://www.bbc.co.uk/programmes/b01dtvpl/features/macbeth