American English Pronunciation
The American English Prounciation podcast from Pronuncian offers some great pronunciation advice and exercises – how to pronounce difficult words, difficult sounds (like that tricky "TH" ), proper intonation and much more! While the advice is great, the podcast doesn't have very much energy and the audio quality isn't as good as it should be for a pronunciation podcast. If I'm being frank, it's a bit boring. While the podcast doesn't appear to be updated any longer, there are many past episodes to listen to. PS. Listen if you are focusing on the American accent.
Zapp Vocabulary and Pronunciation
With much more energy, and better production value, Zapp engages the listener better, but without supplying as much useful content as a podcast like American English Pronunciation. However, it is much better for anyone learning the UK accent. To really benefit from this podcast, you need to buy their e-book. I'm much more a fan of podcasts that don't require additional purchases, but it's still a great podcast to improve your vocabulary and pronunciation!
Learn English with Rachel
As Rachel says, this is a podcast for high intermediate to advanced English learners. There's a good combination of pronunciation, vocabulary, and conversation episodes.Kudos to Rachel for making an entertaining, helpful, and well produced podcast! Though not mentioned in the title, Rachel's podcast focuses on American English.
English Pronunciation & Language Lessons
Out of circulation, Elemental English still has a decent amount of episodes of very high quality to help you pronounce words and intonate more like a native speaker. The listening exercises are great too. This is another American English pronunciation podcast.