The site says "it is almost certain that these machines can switch between cannon-ranged mode and a lance-melee mode." The class's English name is not yet known, but the Korean translates as Armored Castle. You can view the hour-plus press conference via the video after the break, but be warned that it's in Korean and lacks subtitles.
Aion's 4.0 patch is scheduled for December 20th in Korea. There is no word yet on a European or American launch date.