To get started, log into Facebook (as if you weren't logged in already) and open up Farmville. Select the free gifts button, but instead of choosing a gift to send right click on the button and select 'Open in a new tab' or 'Open in a new window'. Keep repeating this process for as many times as you want. For every new tab or window you open, you can send another gift.
The number of new tabs/windows you can open is based on how powerful your computer is. If your computer is old and slow and you try to open 100 tabs/windows, you will likely crash your computer and have to start over. It's best to start with a small number such as 10 and see how your computer handles it. I also recommend doing this early in the morning or late at night when Facebook isn't as busy.
With each new window or tab you have open you can pick a different gift to give to your Farmville neighbor. Once you've selected the gift and the neighbor, click on confirm and send it. This trick is also known as the Farmville Unlimited Gifts cheat because you can open up as many windows or tabs as your computer can process. You just have to make sure you open them all back to back. If you send a gift and then try to open a new tab or window, it won't work. Make sure all your windows are at the confirm and send screen before you start sending those gifts!
Don't forget to teach your friends this trick so they can return the favor. This is just one of my Farmville cheats. Visit my website at http://www.squidoo.com/