Individual Sounds
Adrian Underhill's Phonemic Chart
Published by Macmillan, this site has an interactive chart with audio to demonstrate the sounds of English.
Is the Adrian Underhill phonetic resource useful?
Different British Accents
British accents can be difficult! Use this resource from BBC Radio 4's The Listening Project to listen to real English people from different regions - you won't find these accents in coursebooks!
If you find something interesting, don't forget to share it in the I listened to discussion board! 
Is the Listening Project resource useful?