Walls and Ceilings - Opening up a Load Bearing Wall

I want to put a 6' to 8' opening in between my dining room and living room and the wall seperating the two is a load bearing wall. I know I need to replace the existing studs with a beam spaning the new opening. I'm pretty sure I need to use 2-2X12's with 1/2" ply sandwhiched in between them for the beam. I know I need temp. support walls in place while getting the beam in place. What I'm not sure of are the exact steps, in order, to accomplish my project. If I want about 12" above the opening do I need to put cripples in or just the beam? I would like to know what to do once I have the wall down to the existing studs.

I just removed a load bearing wall in my house, but it was 18' long. I called some local lumber yards, and found one with an in-house structural engineer. I faxed him my hand-drawn floorplan with dimensions, and he called me back with my options. I order the material (They called for LVL beams, which are 18' long. There was only $100 each for 18' lengths, and I needed 4 of them), and had a buddy come over on a weekend. We built a temporary wall on one side, then knocked the load bearing wall over. We put in our vertical posts on each side, and started putting up the beams. As we were putting the beam up, we had to use a sledge hammer to get them all the way in. As we did this, our "temporary" wall started falling down. This was because we trasferred the weight off of it and onto our new beam. Once we got our new beam up, we removed the temp wall, and that was it. It took us only 5 hours to do a 18' span that needed 4 beams put up.

I would suggest doing what I did, and call some local lumber yards. They will be able to help you. I tried some national stores (The big orange store, Lowe's, etc..), but they didn't have a clue what I was trying to do.

Good luck!