Sources that can help you puzzle out the text through context and/or actual pronounciation guides.
Dictionary of American Regional English (DARE) - a record of regional variations of American English. It is different from other dictionaries in that it does not include words that are commonly used throughout the United States, but rather focuses on the regional aspects of our language, documenting words, phrases, and pronunciations that vary from one place to another.
Oxford English Dictionary - A source for the history of a word, when it first entered use, what it's original meaning might have been and how it has changed over time, how it was originally pronounced, how it is pronounced now, etc.
IDEA - International Dialects of English Archive is a database of audio
North American Dialects - This site is really ugly, and is done by an amateur, but there is quite a lot of useful information
DialectBlog - Created by an actor and dialect coach
Illuminations Media and Touch Press have an iPad app of the Sonnets read by a variety of actors. You can watch the videos from them all (yes, all 154) at the Touch Press website
The British Library captured audio and language differences from all over the UK and they have two different sets of materials up.
Shakespeare's Original Pronuciation - A CD in the UWM Library's collection in which you can hear, based on scholarly research, how Shakespeare's words sounded in his day - why certain rhymes worked then that don't seem to now.
Where Words Prevailed - A video about Cicely Berry, the remarkable speech coach for the Royal Shakespeare Company that is in the UWM Media Library
Working Shakespeare - a video series avaialble in the UWM Media Library that looks at how to perform Shakespeare. There are 5 workshops: Workshop 1. Muscularity of language: motion and rhythm -- Workshop 2. Under the text: subtext and the world of the play -- Workshop 3. Prose and verse texts: language and imagery reveal the character's inner landscape -- Workshop 4. The whole voice: its sounds and range -- Workshop 5. The voice preparation workshop.
Can you locate the source of a quote that you find in a play? Sometimes even the playwrite gets it wrong. Here are some sources that can help.
Open Source Shakespeare - keyword searching across all of Shakespeare's works, the sonnets included.
Bartleby - search across a variety of sources, including Emily Dickinson, Lives of the Saints, Walt Whitman...