smash, moderator at the SteamPowered forums has posted on our forums to inform us of some information given to us from Valve's Chris Bokitch. In the light of the recent fake posts from people posing as Valve Software staff, this announcement from Chris should certainly help us to know what to look out for in the future:
There have been several fake "Half-Life 2 Gone Gold!" posts made in forums across the community by people masquerading as Gabe. When Half-Life 2 goes gold, it will be announced via a wide-spread press release. It will be posted many, many places, including the news here and at half-life2.com.
You'll also hear a collective cheer rise up from the Bellevue area, if you're within a few hundred miles.
So it's back to the waiting game, however, if all official estimations so far are true then we should be seeing Half-Life 2 in the next six weeks and the waiting game is nearly over... Watch this space.