They sell a kit at Auto zone for custom intakes. It comes with a hole saw, rubber grommet, and an assortment of plastic nipples for the PCV hose. Its cheap and looks cleaner than a brass fitting theaded in.
You will need a 3/8" barbed fitting for the PCV hose. My old setup had a brass fitting. Now I am running a chrome plated one that I purchased from Summit.
Back when I used to fabricate and sell adapter tubes, I machined 1/8 NPT bungs that I had TIG welded to my tubes. A welded bung is the only way to approach this modification. Unless you want to risk having a nut come off and get sucked into your turbo...