Update: Bethesda's mouthpiece Pete Hines clarified overnight that "There is no new version of [TES: Arena] coming out." What we saw on the Australian Classifications Board website was a "mix-up".
"It apparently was never formally in their system because the release of Arena pre-dated [the Australian Classification Board's] existence," Pete Hines told Joystiq.
"This is simply an error on [the classification board's] part. It should just say PC, not multiplatform. We've notified them and they're going to fix. There is no new version of the game coming. Just a clerical mix-up."
Original: A new listing for the original Elder Scrolls game - Arena, by the classification board in Australia suggests that a re-release of some sort is on the way.
We have no idea what platform this could relate, although some sites are suggesting that it could be a remake for mobile and tablets running the lists of iOS and Android. It could of course also be a re-release for Xbox LIVE and PSN.
The listing states that the game is multiplatform.
Let's hope we find out more soon.