This excerpt is from the Kararite Korner web site, with Nehemia Gordon (site link to the right, and at the end of this excerpt. Happy Counting!
Sunday April 12, 2009 is יוֹם הֲנָפַת הָעֹמֶר Yom Hanafat Ha'omer (Day of the Waving of the Sheaf). When the Temple stood, this day marked the official commencement of the grain harvest (Dt 16:7) and sheaves of barley were cut and brought to the Temple as a wave-offering (Lev 23:9-14). This day also marks the beginning of the 50-day count to חַג הַשָּׁבֻעוֹת Shavuot (Pentecost; Feast of Weeks). Yom Hanafat Ha'omer is counted as Day 1 and Shavuot as Day 50.
Go to this link for a list of the counting for each day: http://www.karaite-korner.org/omer.shtml