Rabbinical Assembly's Passover Guide — Explains the holiday, Conservative observance, "Kosher for Passover" and much more. New this year is the RA's change in policy to allow the eating of kitniyot during Passover, starting on page 6!
My Jewish Learning — MANY wonderful Passover resources including how to create your own Haggadah, sources for seder music, supplemental readings, recipes and more.
Sidduraudio.com includes audio files of selections from the Haggadah (those passages typically sung at the seder). They may be especially helpful for having religious school students and other learners master portions of the Haggadah.
The collection of Passover resources below is courtesy of JVillage Network. MANY great ideas to explore!