Rehearsal Pro is an updated version of the versatile app that enables you to upload a script, highlight it and most importantly record any parts you like. Then, for example, you can play back the audio (while you are driving along) and speak your lines in between the responses of other characters. It’s fun to watch it automatically scroll down as you listen (though not while driving of course). In the early version you paid per script but this one-off fee of £19.99 enables you to upload as many scripts as you wish.
Order from the iTunes Store.