Aperture allows you to shoot tethered direct to its library, no other software / plugins needed. Afterwhich you can also process the images from within the application. If you'd like a straightforward workflow, this is the one.
However, you may have a preference for the capabilities of processing in Lightroom, which in my opinion is superior to what aperture is offering at the moment. In this case, best to follow the suggestion of our bro, shoot via EOS utility for eg, and point Lightroom to the capture folder.
You can also shoot tethered to Aperture, and then use Lightroom, but i think you'd probably need an intermediate process of exporting the master raw files (due to the way aperture handles the library files). This takes up more time.