When does the counting of the omer begin?

Answer 1

The counting down of the omer is the counting down of when the Jews were to receive the Torah- the greatest, most valuable present the Jews have gotten. the counting down for the omer is the 49 days the Jews had to become pure in order to receive our present.

Answer 2

We begin counting the Omer the day after Passover. Interestingly, the Sudacees (old strand of Judaism, no longer in existence) rejected the notion of the oral law, and so they began the count on the day after the Shabbat following Passover. Sudacees aside, all the main Jewish holidays are considered 'Shabbat' as no work is done on them, and therefore the counting of the Omer begins the day following the 'Shabbat' of Pasach. However, the Sudacees did not consider that the holidays were really 'Shabbat', so if, for instance, Pasach fell on a monday, they would wait until the day following the next Saturday (the following Sunday) before beginning the count.

Hope that answers your question.

Shalom

Joel