People identifying as LGBT are not too common in media, but The Simpsons has made an effort to be inclusive. Some of these are quite well written too. Please be aware that some of the characters on this list are not treated as sensitively as others.
As Dana Delany (Katherine Mayfair) says, "I do more than just kiss Julie Benz on Desperate Housewives." But James Denton (Mike Delfino) is dubious as to how the audience would react to a real "heavy duty gay storyline."