At the command line:
$ git clone http://github.com/DataSounds/imSound.git
$ cd imSound
$ python setup.py install
Or, if you have virtualenvwrapper installed:
$ mkvirtualenv imSound
$ workon imSound
(imSound) $ git clone http://github.com/DataSounds/imSound.git
(imSound) $ cd imSound
(imSound) $ python setup.py install
If in doubts while using virtualenvwrapper take a look here..
pygame is a necessary package to use imSound, as well DataSounds. Both of them can be installed using pip. If you use virtualenvwrapper this could be done inside your virtual environment.