Does anybody know if Killer Instinct is going to come out for the Virtual...

Killer Instinct is very unlikely to appear on the Virtual Console due to the buyout of Rare by Microsoft! However, Rare only creates Nintendo games for the Nintendo DS. Also only the Rare supported Donkey Kong franchise remains owned by Nintendo after the buyout, so it is pretty likely that Donkey Kong 64 will be the only N64 Rare supported game to be released on the Virtual Console!

As for Mortal Kombat, it is possible for its release for there is no mention of Acclaim pulling out or anything from developing for Nintendo as such! Don't forget too that Mortal Kombat: Armegaddon for the Wii was released the previous year so it is pretty likely for Mortal Kombat 1, 2 and 3 to appear on the VC if a Mortal Kombat game was released on the Wii! Since Nintendo may have subjective thoughts of releasing games, they would probably release the SNES versions of the games! Hope I helped!

However, you can still play Street Fighter II from the SNES section of the VC, which still has virtually similar gameplay to Killer Instinct! In fact, Killer Instinct adopted the moves from Street Fighter II! Once you have the learnt everyone's moves, you are good to go!

its Already out

Killer Instinct was made by Rare not Nintendo also Mortal Kombat was made by Midway(now owned by Acclaim), as Rare is owned by Microsoft it is unlikely you will see any Rare games on the Virtual Console, however as Viva Pinyata is coming to the DS (also made by Rare) its at least a distant possibility.