I recently put together an Angle on Bow Calculator that can be printed off and cut out for use. It has three basic parts that take in the basic information that AoB calculations need. Target course heading, your sub's course heading, and your periscope view bearing.
Unlike some AoB calculators, this one will give you accurate AoB readings without doing extra math with the periscope view bearings. Printable instructions and the three parts of the calculator can be found at:
http://mysite.verizon.net/ress1z18