The tclservices package provides access to the Mac's Services menu, allowing Tcl/Tk applications built against the Cocoa frameworks (Tk-Cocoa) to function as both providers and consumers of services. (Tk-Carbon is not supported.) With tclservices, Tcl/Tk applications can send data to other applications via the Services menu, and can also provide functionality that can be accessed from the Services menu.
More information: http://opensource.codebykevin.com/native.html#tclservices