"Speaking to the developer's Doug Lombardi, he initially re-confirmed that Half-Life 2 has been announced for Xbox, then went on to clarify the PS2 situation, saying that: "At this point, there are no plans to publish a version [of Half-Life 2] for either of Sony or Nintendo's current systems."
Of course, this means Valve's sequel looks like it will remain exclusive to Xbox in this generation of consoles - somehow, we think Microsoft might be smiling. However, it is highly possible that we'll see Half-Life 2 appearing on the next machines from Sony and Nintendo.
When questioned on the HL2 for PlayStation 3 and GameCube 2 reports, Lombardi told us: "Valve is obviously interested in hearing more about their [Sony and Nintendo] next-generation plans and discuss the possibilities of doing something with them."
I copied this off of www.hl2central.net, and they got the info from www.computerandvideogames.com/