I guess you could take it to a machine shop, but I would just do it myself. I did it with my dremel and a combo of sanding drums and flapper wheels. Just use the old intake gasket as a template for the gasket matching. I used the sanding drums to remove the bulk of the material and then the flapper wheel for the finishing work. For the head ports I just did the opening and then blended it back an inch to smooth the transition. To keep the metal out of the head I covered all the ports except the one I was doing. I then used half a rolled up shop rag in the port I was working on and uses some of my kids playdoh on top of the rag to completely seal it.
I'm sure my job wasnt quite as good/extensive as the porting that SHoSource does. I just like to try and do what I can myself.
Also, make sure you wear a mask...aluminium dust is not good for you.