After endless tweets to Channel Ten (Australian TV network that airs Supernatural) on Twitter, they finally replied with some information on the release of season 5 in Australia and said the following:
@RT Supernatural At this stage we're looking at a 2010 launch for the boys. Sorry, we know... it's going to be a long summer.
I understand where they are coming from. The CW has scheduled a few mini hiatus (there is one this month), so it's really hard for TV networks in other countries to air the show. So it's not a bad move for Channel Ten, at least we won't get interruption when it is eventually on air.