Hebrew Calendar Science and Myths
A collection of resources concerning the calculation of the Hebrew calendar.
http://www.geocities.com/Athens/1584/

Jewish/Civil Calendar Program
Interactive Web program that prints out Jewish and Civil calendars side-by-side. Does not list holidays in either calendar. Source code available.
http://www.uwm.edu/~corre/calendar.html

Kaluach.net
Online Hebrew civil calendar portal. Also receive email reminders of holidays and personal events.
http://www.kaluach.net

Hebrew/English Jewish Calendar with Candle Lighting Times
Perpetual calendar for thousands of locations world-wide.
http://www.chabad.org/calendar/

Kaluach
Hebrew and english calendar for Windows. Displays a Hebrew or civil month with holidays, Shabbat portions, and halachic times. User data can be added.
http://www.kaluach.org

This Month in Jewish History
List of notable events in Jewish history, organized according to Gregorian calendar dates.
http://www.wzo.org.il/en/resources/expand_subject.asp?id=144

Hebcal Jewish Calendar
Complete Hebrew calendar program for Unix and Windows. Candlelighting times, holidays, Omer counts, and Torah readings. C and Perl source code available, as well as a Windows executable and links to Web versions of the software.
http://sourceforge.net/projects/hebcal

Jewish Calendar - Hebrew Calendar
Explains the relationship between the Hebrew civil calendar and Hebrew religious calendar and describes the history of the Hebrew month names.
http://www.angelfire.com/pa2/passover/jewishcalendar.html

Jewish Holidays
Dates of all major and minor Jewish holidays and fast days, with explanations, observances, and links to other articles of interest. From the OU.
http://www.ou.org/holidays

Jewish Calendar
Interface for finding dates in the Hebrew calendar, with holidays and memorial days. Uses PHP calendar software.
http://mike-r.com/%7erechtman/jh.html