Moffiosso,

Go into Maya's Command Line and type source *script name*. Then select that line and middle mouse drag it to the shelf you want it in. Click the black arrow to the left of the shelves. Select Shelf Editor. Here you are able to add a pop-up name/description to your tool as well as an abbreviation for it. You are also able to link your icon to your tool as well.

Hope that helps out.