If my pronunciation students have iphones or ipads, I recommend they try out Otterwave, available in the Itunes Store (it’s not free). Although the app has a British flag on it, it uses American pronunciation models.
Otterwave provides a feedback loop so students can work on improving their pronunciation of English; students record themselves following modeled sentences, and the program shows them how their speech production compares to the models.
Students can see whether they should adjust the speed at which they speak, or the timing that words and syllables should have. They also get feedback on segmentals (vowels and consonants) accuracy, getting a score that tells if they are getting closer to the target sound, or not.
Students or teachers can create new sentences also, once they’ve gone through all the possibilities that are included in the program. And students find it helpful to be able to work on their sound, on their own time, and know their progress. They bring their results back to me, their teacher, and we discuss the accuracy of the software response, and I review and reteach any areas that students need.