Too many possible variations at the moment: Node.js node.js, Nodejs, NodeJS, nodeJS, etc. Personally I prefer NodeJS, remove the period and keep it capitalized since it's a noun.
The official name of Node is "Node". The unofficial name is "Node.js" to disambiguate it from other nodes.<p><a href="https://github.com/joyent/node/wiki/FAQ" rel="nofollow">https://github.com/joyent/node/wiki/FAQ</a>
IMO no. It's a rather new ecosystem. Overtime a dominant variation will emerge. Even if someone did come to a conclusion of what should be the correct variation how would it be enforced?