Nimen hao!
I would like to recommend a multimedia book "Learn Chinese Pronunciation". This book is made for
iPad or iMac with iBooks. There are a lot of interactive exercises and quizzes to help you learn and practise Chinese Pronunciation.
Book link:
https://itunes.apple.com/us/book/learn-chinese-pronunciation/id711081515?mt=11
Unfortunately there isn't a version of this book for other systems????
But you can watch the free video Pinyin lessons on their website , which is www.litaochinese.com
Wow, that sounds great. Does this also exist for Android... or Windows PC?