Instructions
Check your local hobby shop. Some hobby shops have game nights you can join. If the game is already full, they may also know of other games you could join. Use your local hobby shop to post interest in hosting a new game of your own.
Ask your friends or coworkers if they know anyone in the area who plays D&D. Since role players usually have tight-knit groups, it may be possible to find a game through people you know.
Visit AcessDenied.net for a large player registry for any game. The information is not updated regularly so you may come across inactive contact information, but it's worth a look to see if you can find some game players near you. You could also check game specific player registry sites if you can't find enough specific information on AcessDenied.net.
Search for a Yahoo.com group. Since many local gaming groups need to send out messages to their players, they often start groups, and you may be able to join a Dungeons and Dragons game that way. If the group is private, you may be able to send a message to the group organizer and see if they know of anyone looking for new players.
Browse game forums to find a "Looking for games/gamers" section. You can look for posts regarding new games or start your own thread about a game you'd like to start or join.