Rosh Hashanah and Yom Kippur
Essays, audio and the laws from the Ohr Sameach yeshiva.
The Complete High Holidays
Extensive collection of articles on every aspect of the High Holidays: Elul, Rosh Hashana, Yom Kippur, Sukkot and Simchat Torah; interactive quizzes; recipes; Ask-the-Rabbi; full calendar; holiday services search. (From Chabad-Lubavitch)
The High Holidays with Aish
Aish HaTorah site for Rosh HaSana and Yom Kippur. Articles, instruction, insights, plus family activities.