Jane Lynch is to appear on an episode of 'The Simpsons' next season.  She is the actress who plays Sue Sylvester, the ruthless cheerleader coach, on 'Glee'.  She will be playing Homer's new assistant at the nuclear power plant.Jane will take a little inspiration from her current roll on 'Glee' for the episode.  Here is what 'Simpsons' executive producer, Al Jean, has to say about her roll:

“This woman seems terrifically nice, but then it turns out she’s just completely undermining him every step of the way and gets his job — until he can discover her one weakness with the help of Ned Flanders,”

“She can do edge, sweetness, and a mix of both,” he says of the actress, who recorded her lines last week. “I’m just embarrassed we didn’t ask her before she was so successful because she’s funny in everything she does. We were very happy when she said yes.”

[Quote taken from: EW.com - http://insidetv.ew.com/2010/12/14/simpsons-jane-lynch-guest-star/]

Perhaps Homer or Bart will show up on an episode of 'Glee' in the future?  Probably not, but cartoon stars have been known to make cameos on sitcoms... Jus' sayin!