You can find a list of servers from various websites like the following:
When you click on "Multiplayer" on the main menu you will be brought to the screen which lists the servers you have bookmarked.
Click on "Add Server". Enter "Crazy Fools" as the server name and "minecraft.crazy-fools.co.uk" as the server address. After you have clicked on Ok, Crazy Fools will be listed and it will show if the server is currently running as well as how meny people are on it. To join the server click on it and then press the "Join Server" button (Note that if the server is down or if it is full you will not be able to join it).
You can also directly connect to a server by clicking on the "Direct Connect" button and entering the servers address. When you use this method it will not add the server to your server list.