A few suggestions for anyone needing to face the examiners on Shakespeare's The Tempest. Of course, the notes to any decent study edition (Oxford, Cambridge, Arden) will take you a long way, but when it comes to tying it all together a few short guides can be very helpful.
Books
With any set text, it's always worth checking to see if there is a guide on Penguin's excellent, now-sadly-out-of-print Critical Studies series. And indeed there is. Sandra Clark's short book on The Tempest covers background, themes, context etc very clearly and thoroughly.
Rex Gibson's guide to the play in the (in print) Cambridge Student Guides series place a lot of emphasis on context and different modern critical approaches.
Greenwich Exchange encourage authors to go their own way, and Matt Simpson's Student Guide to The Tempest has a nicely personal feel.
Neither of these has a huge amount on commentary on a passage, so if you may need to write in detail on a chunk of text, Peck and Coyle's How to Study a Shakespeare Play has lots of tips. The title is unexciting, but accurate (textbooks have a pleasing modesty and directness).
Online
Revision Guides
The main points are outlined on the Cummings Guide page
Thorough study guide by Andrew Moore on universal teacher
Cliffs Notes
Audio
Podcasts of lectures by Dr Emma Smith of Hertford College, Oxford. Link from her home page (or go direct to iTunes U). Her lecture on The Tempest addresses the question, 'Is Prospero Shakespeare?'.
Talk by Penny Gay on 'Cannibals and Colonization in The Tempest'
Video
One-hour lecture by Professor William Carroll (University of Boston), Shakespeare's 'The Tempest' and Early America (starts after four minutes of preliminaries) - lots on context and later versions / interpretations.
Professor Marjorie Garber (Harvard), Lecture on The Tempest - main points discussed in a seminar
