Do you want to practice, or do you want to receive feedback? With language exchange, practice is easy, but critique/feedback may not be part of the interaction. This is what I do with my students. I record our conversations and transcribe them. I also record a reading from the net (news article) and critique their pronunciation along with my reading afterward so they can hear 1) themselves and 2) a native speaker. Use your library, iTunes, or Google to find accent reduction if that is what you are interested in. There are also materials devoted to pronunciation.