The very latest I had heard is that right now (as I type) there is a compile that is ready for Linux. exe is, from what I understand, beavering away trying to iron out the very last problems and as soon as he's able to confirm that it is a true stable client I'm sure there will be a release to follow!
So.. Linux Lovers.. get your Manic hats on and get ready to join in!
Also: If you, or someone you know can code... and perhaps have some interest in helping. Remember that this is open source and the future of the game depends on people that are willing or eagre to come forward and help provide input!