> Where can I find a community that offers games with that rule set?

Dragonsfoot bills itself as "the home of 1st Edition AD&D" on the web. They have many resources for AD&D, including character sheets, adventure modules, an e-zine called Footprints, and a very active discussion forum. Their URL is http://www.dragonsfoot.org/

You can purchase PDFs of 1st edition AD&D materials at http://www.dndclassics.com/

OSRIC is a simulacrum (retro-clone) of the 1st edition AD&D rules. Get it free at http://www.knights-n-knaves.com/osric/