Okay, so yes, Im a practice tracker-holic. Ive done everything from notebooks to my computer to this whole grid that was so complicated that only I could understand it. Anyways, this is the best and easiest way of keeping track of my times EVER!!! It times you, then puts everything in a nice little bar graph for ya! And as for editing the previous day... If you change the date on your iPhone/iTouch (under settings), you can then go in, add the time, and then go back to the current day. Dont know if it deletes your times between, but it does work. Anyways, this app is awesome and Im telling all my friends!
LeafDeafViolinist about Music Journal Pro - Practice + metronome app to log time and bpm