Yeah, Vcore is high. Past 1.45v they get really hot fast. Sounds about right for temps in a slightly warm room at that Vcore. Try lowering your Vcore if you can and still keep your OC stable, or try to get that water cooler.
You can try to keep your 3.4Ghz, but try lowering the Vcore one notch at a time, then run folding@home or orthos for a long time to test your stability. When you hit the point you are not stable, up the Vcore one notch (might take days).
Depends on your BIOS settings, and your hardware. Personally I have to set mine to unlinked, and set the FSB and memory frequency seperatly. If I choose linked it wants to run my memory at 1600Mhz 8O . So my FSB is set to 1600Mhz, my memory is 800Mhz. That is 1:1, but the math is weird.
Ok, your RAM should be running at 800Mhz (DDR2 = 400Mhz x 2) and min spec voltage. Your CPU should be running at 400Mhz FSB (400Mhz FSB x 9 multiplier = 3600Mhz). I can't tell you for sure what voltage you should be using to achieve this OC, you can search around the net to see what other people with your setup have done (no problem with your setup). I can't find out if the E6600 uses the same stock Vcore as the E6400, if so I achieved a 50% overclock with Vcore of 1.4v.
EDIT: You can check if you are 1:1 using cpuz on the memory tab.