Perpetual Calendar--On screen calculator that will translate a year on the civil calendar to the Hebrew calendar.
Hebcal Interactive Jewish Calendar--Download this calendar that will work on all computer platforms.
PilotYid--If you use a Palm Pilot, check out the Jewish goodies at this site.
Babylon--Download and install this free program and you can right click on any word on any English web page and get its equivalent in Hebrew. (check)