Postal III is the much anticipated third-person shooter to finally succeed the Postal II game that was released back in 2003. The original Postal and Postal II games boasted native Linux clients and for the past few years Running With Scissors has said there will be a native Linux client for Postal III. Complicating the situation though is that Postal III is running off Valve's Source Engine while the earlier Postal game had used the Unreal Engine. I can't talk much more about the Source Engine at the moment, but as most know right now there isn't an official Source Linux client that's released to the public.
This past February, Running With Scissors still planned to have the Postal III Linux client ready in time, but one month later Vince Desi was less optimistic but still interested in seeing a Linux client.
Running With Scissors recently announced that Postal III would be released for the PC on the 3rd of November, so I followed up with Vince regarding the Postal III Linux client. Vince basically says that it's now "doubtful at this time." It may come later, but not next month.
Also missing from the Linux game scene right now is id Software's Rage, but we might see Rage on Linux in 2012. At least this calendar year we still can look forward to the Doom 3 source-code release and other events.