What is the best phonetic app for the iPad? I'm not a native english speaker and so I'm looking for an app to teach my 4 year old daughter with spelling and speaking. She's speaking English very well and very confident in communicating with her friends in English. 

However, her teacher is saying that her phonetic is not quite good yet. She's missing some sound, eg. 'p' vs 'b'. Also, she's not good in dictating exercise, meaning writing down word when others read it to her.

So my question is what will be the best app for my daughter? 

My daughter loves SuperWhy show but I'm not sure if their app is good. I wonder if anyone can list his/her favorite app here so we can vote on them.
This is a little left field from the answers you requested, but I would suggest turning on the feature to allow screen reading in the accessibility settings area, which allows any app that uses a standard text area that can be cut/paste to be read aloud.  In this way as she encounters test in any app, she can have portions of it read to her, and the diction is pretty good as a rule, allowing her to learn by real world example.