This is just short snippet on how to install Node.js (any version) and NPM (Node Package Manager) on your Ubuntu/Debian system.

Step 1 - Update your system

sudo apt-get update
sudo apt-get install git-core curl build-essential openssl libssl-dev

Step 2 - Install Node.js

First, clone the Node.js repository:

git clone https://github.com/joyent/node.git
cd node

Now, if you require a specific version of Node:

git tag # Gives you a list of released versions
git checkout v0.4.12

Then compile and install Node like this:

./configure
make
sudo make install

Then, check if node was installed correctly:

node -v

Step 3 - Install NPM

Simply run the NPM install script:

curl http://npmjs.org/install.sh | sudo sh

And then check it works:

npm -v

That's all.