isaacs/npm — pull request #2155 by nmorse (2012-02-13 23:11:02+00:00)
Title: More helpful instruction for install using sudo on a 'notroot' server.

... Yes, if you are getting errors, you now know that sudo 'curl ... | sh' does not work... helpful to suggest running 'curl ... | sudo sh' instead, which has worked for several people.
re: http://stackoverflow.com/questions/6752873/node-js-npm-install-fails