Hopefully sometime soon. It was never announced and probably suffers the same fate as Half Life 3.
On November 10, 2012!
It premiered on October 10, 2010.
It came out yesterday (17th September)
Season 4 of My Little Pony: Friendship is Magic has already started. The two-part premier aired on November 23, 2013.
When the cows come home
Season 5 of My Little Pony: Friendship is Magic is the most recent season to be announced. It is set to be released later in 2015. As of February 2015 there is no information about any additional seasons to come.
This episode has already been released.
It is not known. The origin of Discord is not discussed.
Well, they always get played on The Hub, but you can also check them out on iTunes or YouTube.
It has not been revealed when Discord came to Equestria.
It won't. Sorry. Season 3 is only having 13 episodes. But have no fear! Season 4 episode 1 will come out on November 23, 2013.
My Little Pony: Dress Up Pony - Cherilee Goes to School, or the other Dress-Up Pony sets all come with extra clothes for dressing up.