GOG Galaxy for Mac is a new application that lets you access your Steam account from your Mac OS X Leopard. Although you may be able to play the game using your browser, the truth of the matter is that you will probably have better luck if you are able to log into your Steam account. The application is free, but it does not allow you to download anything other than the free copy of the game. The application will still allow you to play the original game that you have purchased.
The GOG website offers a variety of free games, but the majority of their offerings are free games that require a paid membership to obtain. When you become a member, you will gain access to all future GOG games as well as a host of free games. This is definitely not what you would consider a deal, but it is certainly better than having to spend money to play the same games over again.
The application is available for free through GOG, but you will find that once you become a member, you can download as much of the software as you want and unlimited games will be available to you. It is truly a unique opportunity to have a free application that also allows you to play games on your Mac. Whether you are a hardcore World of Warcraft or Runescape player, this application is something that you will not want to miss out on.