I'm leaving on a trip Tuesday and wanted to continue working from the "Ear Training For Contemporary Musicians" book while traveling. I need to pack light since I'll be going through airports and work computer and clothes will take up most of the room in my baggage. I'll be taking my Mac Air laptop and iPhone. I can copy the CD's onto the iPhone and laptop, but a lot of the exercises involve playing notes. Any suggestions on technology to help? Should I install a keyboard app on the iPhone? Software on the laptop? Or try to find a small keyboard with an earphone jack that will fit in my carry on? I can't hook my personal computer up to the company's network, so I won't have much Internet access.