Well, I probably only know as much as you do, but there are two things to know here.
1) If you're shooting TB cleaner into the manifold, you don't want to flood it with the stuff. The car should be able to idle on it's own and keep runnning. You want to be sure that the TB cleaner is able to be atomized as it passes though the manifold. If the car is stalling, you're putting to much in, or you're too close. My mechanic had the nozzle a couple inches outside the manifold and sprayed just enough in to keep the car running. The idle will actually rise as the TB cleaner is sprayed in (at least it did on mine.)
2) Like above mentioned, just take off the upper intake manifold ("UIM") (but go buy your gaskets first. There's two of 'em one for each side of the manifold). Use the Valvoline TB Cleaner, and there's also some stuff that foams up inside. A few go overs with the combination of the two has had good results with other people.
Do a seach of the forums. There's plenty of thread about cleaning it. Also, in the FAQ section there is a diagram and explaination for removing the UIM. That should be enought o get you started. But search for the other threads as well. Someone a couple months back had pics of before and after.
