www.innov8tion.com/apps/igtask-for-ical/

It requires the account registration first.  The user can simply provide an email address and the password to register an account on our web site, then download the trial of purchase the licensing.

Main features:

• Two-way synchronization -- supports two-way synchronization of task data between iCal task and Gmail task.
• Multiple task lists -- supports multiple task lists
• Auto/manual sync option settings -- supports auto/manual sync option settings
• Fully compatible with Gmail task and iCal task features.

Disclaimer: iGTask For iCal is not endorsed by Google.  Google might change Gmail task implementation in the future, when such event occurs we will fix the issue accordingly.

The first time iGTask is launched, it will require to go through software registration.  Simply just type in the email address and the password created during the account registration on our web site. 

Upon successfully activating iGTask, there should be a screen to allow the users to set up Gmail account with Gmail email address and the password.

Then the users can set the sync option settings.  There are three sync option setings: Two-Way, sync from iCal Task to Gmail task, or sync from Gmail task to iCal Task.  The two-way sync option is by default.

The users can also set auto-sync interval as well.

Here is how to set it:

Launch iGTask icon on the top right corner menu bar on your Mac, click "Google account setting", in the section of "Custom Domain", you can set the custom domain for your Google account.  Please check the checkbox of "Custom domain" if you are using Google account custom domain, then put in your domain info.  For example, "www.yourdomain.com" is your domain, in the input field below the checkbox, please put in "yourdomain.com" without "www".

When logging into your Google account, in the "username" field, please put in your user name, the custom domain should be automatically populated if you have set it in "custom domain setting".  For example, here is your Google account with customer domain: johndoe@yourdomain.com, in the "username" field, you just put in "johndoe".  "@yourdomain.com" should be automatically populated if you have set in in "custom domain setting".

•  Most of syncing issues is related to the google cookies.  It could be resolved by doing: click "iGTask" icon on the top right menu bar on your Mac, click on "Tools", click on "Clear google cookies"
• Google account with custom domain.  Please check out FAQ entry on how to set Google custom domain.
• If you clear the google cookies and the custom domain isn't an issue, please click "Tools"---"Export log" and send it to: support@innov8tion.com

Click "iGTask" icon on top right corner, click "Sync Settings",  in the section of "calendar options", you can configure the calendar sync options.

If you are not using custom domain for your google account, click "iGTask" icon on the right top menu bar on the Mac, click "Sync Settings", under the section of "Calendar options", click on "Calendar List", it will list all the calendars available.  Please select the calendars you want to sync.