If you are a web designer, the thought of using the command line may put you off of using SASS; you probably prefer using a tool that has a GUI that can do some or all of the hard work for you. If this is true, then you can use the power of Scout to do the hard work of compiling for you, as you will see in this recipe.
For this recipe, you will need to obtain a copy of Scout. It is available from http://mhs.github.com/scout-app/. The latest version at the time of writing is 0.7.1; this is a cross-platform application that will require you to download Adobe AIR. I will assume for the purposes of this exercise that you don't have it installed; you can download it from http://get.adobe.com/air/.