To Download the Minecraft client - @ http://www.minecraft.net/download. We recommend you use the full client, not the web-based option for best performance (go onnn... its only a little download! ;P)
Setup a connection to the Massively Minecraft Server in the Multiplayer section of your Minecraft client - Our Server Address is: play.massivelyminecraft.org. You can also use the IP address which is: 220.127.116.11.