Q: Does Psychtoolbox work with 64-Bit versions of Matlab or Octave?
A: Psychtoolbox doesn't work with 64-Bit versions of Matlab or Octave as of december 2010. We will work towards 64-Bit support and aim to make 64-Bit support available by the end of 2011. This is a lot of effort and the difficulty varies depending on operating system. Our educated guess is that support for Linux should be relatively easy to implement, whereas support for Apple's Mac OS system will be much more painful and slow to implement. You may see partial support for some features already earlier, but aiming for end 2011 is the best prediction we can make at this time.
This means that Psychtoolbox won't work with Matlab version R2010b or later on the Apple system, as R2010b on Mac OS doesn't support any 32-Bit toolboxes anymore. However, installation of a 32-Bit Matlab version in parallel to a 64-Bit version is easy, so this should be more of an inconvenience to you than a major showstopper. Please see Mathworks support site for instructions if the procedure isn't apparent to you.
For Windows (Vista/7) too, one can install a 32bit and a 64bit version of MATLAB alongside each other on the 64bit versions of the OS. Both are included on the Windows DVD. To choose yourself which version to install, instead of using the autorun menu, navigate on the DVD to \bin\win32 or \bin\win64 and run the setup.exe there. You can install both and the order in which you do does not matter. However, install the one you want to use by default to open your MATLAB files last, or you will have to manually correct your file preferences.