Quick and easy installation - leoner/node GitHub Wiki
Install homebrew then:
brew install node.js
or get your mac up to speed with cider.
sudo apt-get install build-essential libc6-dev-i386 lib32stdc++6 git-core
sudo ln -s /usr/lib32/libstdc++.so.6 /usr/lib32/libstdc++.so
git clone git://github.com/ry/node.git
cd node
./configure
make
sudo make install
thanks Travis Swicegood.