Tully - I just did this repair on my 2004 H2 for about $40 and 3 hours.
What you need to do is buy the gaskets & bolts. This is definately a two person job but it can be done. What you need to do about two days before you do it is to spray the bolts and the broken bolt with PB Blaster or Liquid Wrench and let it soak in WELL.
Then remove all the bolts that you can with a socket - I broke off two additional ones when doing mine. After that you can side off the manifold
after you pull the spark plug wires - just side it off a few inches so that you can get a set of vice grips around that bolt stubs.
This is where the second person comes in - the guy on top provides the tork on the vice grips and the the person on the bottom is the eyes becuase you cannot see then while looking down into the motor. Once the vice grips are locked onto the stub they will eventually work free. This is where the three hours comes into play.
After you get them off just drop on the new gasket and bolt everything back together.
I have to do my passenger's side next becuase I have one that just broke off on that side too and I am not looking forward to it.
Good luck bro - been there done that.
Forgot to mention - use Class 90 bolts and you'll never replace them again. Here is the link for them at Fastenal - I had them bring them in for me. The OE ones are crap.
http://www.fastenal.com/web/products...1115929&ucst=t