I found this really neat site: Akhlah. There is a Hebrew letter of the day and Parsha of the week available (plus lots of games, puzzles, and more). By the way, Parsha is simply the weekly reading of the Torah divided up into the weeks of the year. For messianics, it also includes the Haftarah and Brit Chadasha (the complete old testament and new testament, respectively) readings.
It might be important to note on this particular site that in place of "God" the name "Hashem" is used (many observant Jews will not spell out the entire name of God out of respect in keeping His name holy, and therefore will use Hashem, which means literally "The Name", in place of Elohim, Adonai, Jehovah, or YHWH). Depending on how comfortable you are with introducing your children to this level of jewishness, you may want to skim through the site and see what fits your family best.
I love the aleph bet (Hebrew alphabet) presentation. Kids can practice writing using script or block print, hear the pronunciation of each letter, and color a coloring page. You can also print out flashcards.
For even more resources, this site offers info on Jewish history, heroes (like the patriarchs- Abraham, Isaac, etc.), Jewish traditions, info on Israel, and holiday info for kids, including songs for Shabbat (sabbath).
This is a very culturally rich site filled with info for any family wishing to do an in depth study on Hebrew roots especially for young children. Even if you are not Jewish, depending on your family/school goals, you can incorporate some of this into your lessons if you were doing a unit study on the Jews.
As a Christian believer looking into Hebrew roots of my faith, this fit in pretty well for our home school.