According to the official channel on Niconico Douga, Aniplex has made a public appeal for the ED themes of Ore no Imouto ga Konnani Kawaii Wake ga Nai
anime and offered 100,000 yen ($1,100) as a prize. They'll accept applications from June 1st till July 31st and maximum twelve songs will be selected. The seiyu of the anime will sing the songs and the CD will also be released.
The anime will start this autumn.
Source: OreImo official channel