SPOILERS for the current season of Avengers: Earth's Mightiest Heroes follow...
Some good and bad news for us Spidey fans. The good news is that Spider-Man is set to appear in the soon-to-be-deceased Avengers: EMH in an episode entitled Along Came a Spider. However, depending on your taste in Spider-Man voice actors, this news may leave you with a bit of a sour taste in your mouth. According to a recent article by IGN, Spectacular Spider-Man voice actor Josh Keaton originally reprised his role as Spider-Man for the episode, doing the recording back in 2010. However, when the episode finally aired, fans discovered that Marvel had re-recorded Spidey's lines using Ultimate Spider-Man voice actor Drake Bell!
Now, I don't mind Bell as Spider-Man, but speaking as a big fan of The Spectacular Spider-Man, I would have really enjoyed hearing Keaton reprise the role for one last time. Marvel most likely did this to promote brand consistency, catering to Ultimate Spider-Man viewers who want to see more of their Spider-Man onscreen. Although I understand why they did it, it still sucks, and along with Earth's Mightiest Heroes impending cancellation, is just another one of the lame moves Marvel has made in their animation field as of late.
Josh Keaton, a true professional, has taken this all in stride. For his reaction, here's the full article.