NumSemaine is a small application which creates a iCal file with the week's number.This small application makes it possible to generate a file which will post the numbers of week in iCal.
For that, you must:
choose the year of the calendar (option Year) or choose the current date of the first week (option Free), the selected day must correspond with The Day chosen below (Monday or Sunday),
specify if the weeks begin on Monday or Sunday,
specify if the mark in iCal relates to the whole week, only to the first day of the week or only to the first day of the week with schedule event (specify the hour, at 8h00 am by default)