go to amsn sourceforge
and download the tar.gz file to your home directory. once it's downloaded, untar it by opening a terminal and typing:
tar -xzvf amsn-0_94.tar.gz
it will create new directory in your home directory called amsn. the run script is in there, labeled "amsn"
i created a link to it by opening a terminal and typing
ln -s ~/amsn-0_94/amsn /usr/bin/amsn
this way all i need to do is type amsn into a run command