If you use the Google Calendar, it's pretty easy to have the events from your Google Calendar show up on your desktop calendar. To start, you need to get the unique address for the subscription of your Google Calendar. To do that, go to the Google Calendar page and select "Settings" which is at the top right of the page. Select the "Calendars" tab. In the "My Calendars" section, click on the name of the calendar that you want to have show up on your desktop, this will bring up the "Calendar Details" page. On this page, near the bottom is a section called "Private Address". To the right should be a button labeled "iCal", click it and a window will pop up with a long URL. This is the URL that you need to subscribe to from your desktop. Highlight it and copy it to your clipboard.

If you are using a Mac, you can add the Google Calendar events to iCal by going to "Calander" and then choosing "Subscribe...". You can then paste in the URL that you just copied. It will check the validity of the URL and show a panel that allows you to set the settings for this Calendar.

If you are using Windows Vista, open the Calendar and hit the "Subscribe" button. Paste in the URL that you copied from Google. It will check the validity of the URL and show a panel that allows you to set the settings for this Calendar.