The official node.js github page has a rundown for all distros, Debian included. They recommend installing from source:
apt-get install python g++ curl libssl-dev
mkdir /tmp/nodejs && cd /tmp/nodejs
tar xzvf node-latest.tar.gz && cd node-v*
Remember that installing from source will definitely get you the latest software, however sometimes it is more difficult to uninstall all files attached to a specific project. In order to avoid this, use
checkinstall to build yourself a quick package.
I was able to build a .deb package on Ubuntu by following the guide here. This should probably also work for Debian too ;-)