Read before continuing
1. Modify your Xbox at your own risk, I will not be held responsible for any damages.
2. You need to know how to disassemble your xbox 360 and remove the motherboard. 
3. You also need basic soldering skills.
First of all I love the tutorials an xbox-scene and used many of them from time to time so I just wanted to give back.
I've searched and couldn't find anyting about the front fan header so here you go, if there is another tut or post then pass on bye.
I'm a cooling nut and can't stand anything but room temp air coming form my 360. Unlike the old 1.0 xbox with it's two fan headers and four pin molex microsoft left us high and dry for adding additional cooling that can be easly unplugged. Yeah I know about the DVD cable adapter and usb but the problem is your stealing power from circuits that need it and might ultimatly damage your box. This mod pulls 12v power directly form the power supply before it passes through any circuits. And this mod is free if you have an old motherboard laying aroung and a soldering iron.
Stuff you need
1. Soldering Iron.
2. Solder
3. Fan header from old motherboard. They can be difficult to remove without melting so you might want to buy one.
4. 3/64 drill bit or a tad smaller but no larger.
Notice the solder in the holes.
Dont bother trying to remove the solder from the side holes because you can't or I couldn't with my $370 hexacon iron.
I don't think they're drilled all the way through.
I used a 3/64 drill bit to get the side holes clean and I think it did a pretty good job.
Here is the point before bridging.
If you want 12v then bridge R7V7
If you want 5v then bridge R7V6
I know for a fact that the 12v is directly from the power supply.
I'll check the 5v on my ginny pig and update in the next few days.
DON'T BRIDGE BOTH.
This is what 12v should look like after soldering.
And no pointing out my bitchen soldering job. I need new tips.
Flip the board back over and it's ready to go.
Here's a 12v 70mm fan working off the header.
My camera didn't catch the fan spinning but you can see the blue LED's.
My sons setup.
Fan doesn't look to shabby.
The new fan blows so much that you can feel cool air coming from cracks all aroung the covers.
I know it needs a grill but 70mm grills are hard to come by unless you want to pay $8 shipping on Ebay. I'll end up converting a 80mm grill later.
Hope this short tutorial helps someone. 
Now I just need to find another 70mm blue LED fan for my 360. 
Darn spoiled kid.
