I installed via npm version 1.0.27 and node 0.4.9. The package.json file did not include a main entry, so require('gd') was broken. I added main: './gd.js', to my package.json and it worked.
Not sure if you maintain the npm package or not - it lists a forked repo, but you as the author.
the community-maintained version works:
this is also the version registered with npmjs.org
so you should also be able to do:
npm install node-gd