Don't you have a speaker from a PC speaker-system or something? You might need a couple of resistors to get the level right. Or headphones even? I'm not sure exactly the right hook-up but I'm sure Mr Google will be able to suggest something.
As for pitch, there is nothing about the Tone library that stops you getting a high pitch (I don't think). The hardware itself could output 100s of kHz, well outside human (and probably animal) hearing.