Pesach begins at sundown tomorrow, and there are dozens of excellent sites on the World Wide Web that can help you and your family get the most out of the festival. This week we'll survey the best of this year's crop of Pesach sites.

As usual, the Jewish super-sites — big magazine-style Web sites, most with an Orthodox or Chassidic cast — offer the most bang for the buck. Also as usual, Reform and Conservative sites on Passover range between the indifferent to the nonexistent.

You might want to start your Passover surfing at the super site of Aish HaTorah, the Israel-based Jewish outreach group. Its Passover page — http://aish.com/ holidays/passover/default.asp — has just about everything you could want to know about Passover and how to do it right.

Especially noteworthy here: a big section of "Hagaddah Highlights," offering lucid commentary on every aspect of the seder.

There's also a comprehensive guide to Passover cleaning; you can read the clear directions, or listen to them on your computer, using RealAudio software. Other sections deal with the usual questions that come up this time of year — for example, what to feed your pets during Passover.

There's also a pretty good kids' section and a fair collection of recipes.

Another good all-around Passover site has a distinctly Chassidic cast: The 2001 Chabad Passover site — www.passover.net — is graphically gorgeous, with a little something for everybody. The kids may like the "Mr. Matzah" navigation aid and the modest collection of games. The adults will like the recipes and the more detailed information about the meaning of Passover.

A multimedia section includes a handful of Passover songs — including a lively, truly strange rendition of "Dayenu" that sounds like it was played by a marimba band.

This being a very modern kind of site, you can also sell your chametz online, and order the Lubavitchers own shmurah matzah using a secure server and your credit card. Note: It's pricey stuff, but if you're looking for the real thing — guarded matzah whose production has been supervised by a rabbi from harvesting to completion — this is the place.

If you want the Reform perspective, lots of luck; the major Reform sites barely acknowledge Passover.

There's a smattering of information on the Union of American Hebrew Congregations Jewish Parent Page, at http://uahc.org/educate/parent/0407 The movement's "Click on Judaism" site — www.clickonjudaism.com — supposedly a hip outreach mechanism for younger Jews, pops up with timely articles on…Tu B'Shevat.

Jewish.Com — the big Jewish Web portal at www.jewish.com — has a good mix of information and features, but without the denominational cast of the Chabad and Aish HaTorah sites. There are Passover guides for Reconstructionists, for social activists and for "those in recovery." For real novices, there is a glossary of Passover terms.

One interesting feature on this site: a discussion of Passover "weights and measures."

Jacob Richman, a funny guy in Israel who likes to tell others about interesting Web sites, maintains a section on his own site devoted to Passover humor. Don't miss the "Dr. Seuss version of the 4 questions" and the old but still funny joke about the Braille reader and matzah (punch line: "Who wrote this stuff?") It's at www.jr.co.il/humor/pass09.txt

Want detailed information about kashrut issues for Passover? Check out www.kashrut.com — an informative site on kosher living by a "food scientist and kosher food specialist." It has alerts about kosher and not-so-kosher products, information on Passover travel, recipes and more.