An auto-adjusting compass pointing in the direction of the satellite or flare helps you tracing the object.
Notifications can be enabled to warn you whenever a satellite of interest passes by.
The actual data is taken from www.heavens-above.com. They did a great job so check out their website too.
This is NOT the official www.heavens-above.com Android application although the name may suggest this.
Tags: satellite tracker, ISS, satellite spotting