I installed this through Package Control in ST2. However, when I am coding in a .boo file, it doesn't use the syntax highlighting (although it did find booc.exe, I can select it as a Build option and it compiles). I am new to the program so I've had difficulty fixing the issue on my own, and I haven't found anything to help me online. I'd be grateful for any suggestions.
Open up a .boo file, and select View -> Syntax -> Boo to enable highlighting for that particular file. The list of languages is also available from the menu on the far right of the status bar at the bottom of the Sublime window. To enable this language for every time you open a Boo file, select View -> Syntax -> Open all with current extension as... -> Boo and you should be all set.