Credit should be given to my Dad, who told me eagerly that that he saw the International Space Station one night thanks to this app.
He was out camping and used it - it comes multiple times during the day and night, and you will be able to spot it.
Take a look here, it's on the web too!
And get it on the app store here.
Basically, it tells you where to look, what time it will pass and what kind of visibility will be like.
Also, it shows you where it flies over the rest of the world.
Kinda fun especially for the outdoors - I saw it tonight myself and it looked like a shooting star!
PS - It's shining because it's reflecting light off the sun
PPS - It's hard to see at night when it's clear because stars are so bright!