This is a fantastic download. It enables you to play Yugioh against friend or foe alike. Its completely free and you can make virtually ANY deck on it as it contains over 1500 cards.

The download is located at http://www.xerocreative.com. The latest version of this is YVD 8.6.

To download this, go to the above link then look for a page called yugioh virtual desktop. If you have never downloaded any YVD's before then download the top link (YVD 8.6 Installer), otherwise search for the relevant download below.