google calendar

Convert calendar data in Now Up-To-Date to iCal.

Rili is a very simple, tiny calendar

iSync Palm Conduit allows you to use iSync to synchronize contact and calendar

MiniCal is a free, small and simple FileMaker Calendar.

This is an online organizer, group calendar and IM suite.

Copy Oracle calendar into iCal.

Generating a calendar containing the numbers of week in iCal

Dates to iCal 2 is a replacement for Apple's birthday calendar for iCal.

Slacker ToDo Lists is a todo list, outliner, and calendar for Mac OS X.

Email and calendar client.