Online Go:
For playing Go online, most of our members use The KGS Go Server. It is one of the simplest Go clients to use, and it is the most popular Go server in America. Downloading it is fairly simple, you go to the Downloads Page, and click on the large blue highlighted text: "CGoban for Java Web Start." If you don't have Java installed on your computer, there's a download link for it on the page which leads to here.