The brass fitting:

This is what you came for. Detailed shots of the brass fitting and the orifice that you need to drill out.
One side is a 3/8 inch NPT flared fitting that you connect to your gas line. It has the bigger hole, plus you'll notice before you take it appart.

The other side of the fitting is where the orifice is. Its a tiny pin-hole. You take you 7/64 inch drill bit and drill it out. Like I said, I'm no do-it-yourself-er, but this was even easy enough for me.

Here are shots of the brass fitting before and after the drilling was done.

Gas-In

Before Drilling

After Drilling

Then all you do is put the thing back together.