Update:After much time and effort with this writeup, it appears that Calgoo can do all this much more simply. If you like easy, follow these steps:

Further Update: Calgoo Connect is no longer free and easy.

1. Download Calgoo Connect.
2. Install it.
3. Follow these directions.

If you’d rather do it the fun or less intrusive way, follow these directions:

1. Download GCALDaemon and save it where you normally save downloads. Just visit This page and click the link that say “UNIX/Linux/AIX/Mac OS X compatible ZIP archive”. It’s under the “Linux compatible” section, but you don’t need Linux, because the OS X Terminal is compatible. Don’t open it or unzip it, just save the file.
2. Hit Apple-Space Bar to open Spotlight (Or just click the Magnifying glass on your menu bar), and type in “Terminal.” Click the result that looks like a black screen and says “Terminal”. Don’t freak out when it opens up with a boring little cursor.
3. Make sure you have Java 1.5 or higher installed. Just type in:
   java -version
   and hit enter, and it will tell you what version you have. If it’s lower than 1.5, go to java.sun.com and install the latest version.
4. Type in the following command, and hit enter:
   cd /usr/local/sbin
5. Type in:
   sudo unzip
   (add a space at the end, do NOT hit enter)
6. Drag and drop your newly-downloaded file onto Terminal. This pastes in the correct pathname. Hit enter.
7. Now type in each of these commands, and hit enter after each one:
   sudo chgrp -R admin /usr/local/sbin/GCALDaemon
sudo chmod -R g+w /usr/local/sbin/GCALDaemon
sudo chmod 755 /usr/local/sbin/GCALDaemon/bin/*.sh
8. Leave Terminal open

Sweet! Now that GCALDaemon is installed, we can set it up to do a two-way synchronize between iCal and Google Calendar.

1. In Terminal, type this in and hit enter to run the setup program: /usr/local/sbin/GCALDaemon/bin/config-editor.sh
2. Select the “File synchronizer” on the left, and click the “Google Accounts” buttom (screenshot)
3. Click the “New Account” button, enter your Gmail address and your password (twice), click “Verify”, and hit “OK”
4. Click the “New” button (Left of the “Google Accounts” button you just pushed)
6. Select your Google account, your Google Calendar (You may have to hit “refresh” to see them all), and your iCal file. Hit OK, and repeat for as many calendars as you have.

Almost done! All we have to do is make this program run whenever you’re on your computer.

1. Download Lingon here and unzip it into your “Applications” or “Applications/Utilities” folder.
2. Double-click on it to run it
3. Follow the five easy steps here. IMPORTANT: when it asks for the path in step 4, enter this:
   /usr/local/sbin/GCALDaemon/bin/standalone-start.sh

That’s it, you’re done! Now your Google Calendar will always be synced with your iCal! If you change one, the other will change automagically! Now, go ahead and set up Outlook 2007 to sync with Google Calendar as well–it’s much easier.