WebCards can be downloaded from the WebCards Members' Area.
Once you are logged in, click the "Download WebCards Now" button to begin your download.
Please heed the warning at the bottom of this screen. Everybody's download is different and if you let somebody else use your download, they will be able to get support and updates from your licence key.
Once you have the download, you need to unzip it. 7-zip is a great choice and can be downloaded from http://www.7-zip.org.