Installing the pre-packaged Node distributions is currently the preferred installation method. However, installing Node from source is desirable in a few situations:
It could let you optimize the compiler settings as desired
It could let you cross-compile, say for an embedded ARM system
You might need to keep multiple Node builds for testing
You might be working on Node itself
Now that you have the high-level view, let's get our hands dirty mucking around in some build scripts. The general process follows the usual configure, make, and make install routine that you may already have performed with other open source software packages. If not, don't worry, we'll guide you through the process.
The official installation instructions are in the Node wiki at https://github.com/joyent/node/wiki/Installation.