Matt Dodds: The exploit is actually in Internet Explorer 7 on Windows XP machines - the Acrobat Reader is just the vector, which has the "nice" added capability of executing embedded URLs automatically. Version 7.x is not vulnerable and you don't need to update non-WinXP machines.
Anonymous Coward: Foxit is "vulnerable" (in the sense that it can be used as an attack vector) too - the only difference is that there you'll have to be convinced to click on an URL in the PDF file, while with Acrobat the malware runs by just opening the PDF file. Other applications (Firefox, Skype, mIRC, Miranda and countless others) can similarly be attack vectors. The root of the problem is in IE7 on WinXP machines. Microsoft has yet to patch that. Once they do, the problem will disappear.