AD&D is the proper term. If you want that specific ruleset it was republished by...

AD&D is the proper term. If you want that specific ruleset it was republished by WotC one or two years back, used versions also available. If you're more flexible on the ruleset there's Old School Renaissance [1], set of games which try to recreate the rules/feel of AD&D. RGP Geek [2] might be a forum you're interested in. You can likely find a group in your area if you're in a bigger city or metro area at gaming shops. If you use Reddit [3] is a reasonably active place to find groups or players.