To do this you will need to have the Google Chrome Browser installed on your Ubuntu System. To install Chrome, start a Terminal Window and type the following:
wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add - (HIT ENTER)
Close your Terminal Window because you should now have the Google Chrome Browser installed and working on your system.
Launch Google Chrome Browser and goto http://mail.google.com/tasks/ig (Google Tasks webpage). Once on that page you should see your list of Tasks (if you don't see your Tasks List you probably don't have a Google Tasks account. Get one! they are free).
While on the Google Tasks webpage you have to click on the little Wrench Icon in the upper right side of the Google Chrome Browser. This give you a drop down menu list. Navigate to TOOLS-->CREATE APPLICATION SHORTCUT. Click on it and a pop up window will appear.
In the pop window Check the APPICATIONS MENU option and click the CREATE button (if you want a Desktop Shortcut then Check the DESKTOP option too).
Your almost done. Just click on your Unity Dash Home button and type TASK into the Search box. You should see a green check mark icon labeled TASKS. Just drag it onto your Unity Launcher Bar. When you click on the TASKS Icon on the Unity Launcher Bar you will get a nice popup window that gives you access to your Google Tasks. (I guess you could have just drug a shortcut onto your desktop from Firefox but what fun would that have been).