You can have 24-hour time in MileBug!
MileBug uses the settings specified in the iPhone/iPod device settings. To change to 24-hour time, open the Settings app on your iPhone home screen. Tap General --> Date&Time, then turn on 24-hour time. Next time you open MileBug...voila! 24-hour time!
As far as format, you can set the format in the Settings app as well. Tap General --> International --> Region Format. Then select your desired region.