Most pedal/crank threads are 9/16" x 20 tpi, that is all except the one piece crankset normally found on kids bikes & they're 1/2" threads.
Taps & dies are available from here http://www.webbline.co.uk/default.asp?pID=10
Taps & dies are available from here http://www.webbline.co.uk/default.asp?pID=10