Currently Being ModeratedApr 21, 2012 3:40 AM (in response to whitesalmon133)
To change the color of a reminder, you have to create the reminder in a calendar with the correct color. Ctrl-click the reminder in the "Reminders" tab and select a suitable calendar with the color you want.
To change the color of the calendar select it in the Calendar drop-down list, ctrl-click it to open "get info" and set a new color from the color chooser in the upper right corner of the "Info" panel.
ctrl-click and "Get Info" to change the color also works, when you are creating the Reminder-list, see the screenshot below: