Avast 5 is being developed since 2007. Back in 2007 avast! told, they would release version 5.0 sometime in 2008. Well 2008 is gone.
Now they have no fixed date. They have not even released a public beta version yet. So keep your hopes alive, maybe they would release version 5.0 in 2010.
Here is avast! forum thread about version 5.0 http://forum.avast.com/index.php?topic=32320.30
Edited by Romeo29, 27 June 2009 - 02:25 PM.