how to edit the .profile file to have shortcuts for commands?

im really new to unix, i wanted to learn how to edit a .profile script on OSX lion to help me have shortcut for this directory:

/usr/local/cellar/node_modules/node.io/bin/node.io

i want to be able to run the program like this:

node.io -h

instead of :

/usr/local/cellar/node_modules/node.io/bin/node.io -h

for some reason npm hasn't decided to set paths for me, even though i used -g, so going to do it manually.