By forcing Windows Vista to use some default drivers, you can access the unit's memory like a USB memory stick. You just need a software tool to read out the XTAF-file system of the unit.
Step 1: Open the Unit
Step 2: Solder USB Connector to PCB
Then connect the black, green and white wire to the pins according to the picture:
The two left leads are shield and ground, the 3rd lead from the left is the +3.3V power pin which will be fed by our voltage regulator from step 3. The next two pins are D- (white) and D+ (green) from USB. The 2nd from the right is GND again (black from USB). The last pin is shield again (as you can see).
Note: Think forward and carefully adjust the cable length to your USB port to fit the case length and inner height! The parts have nearly no space to the top (I needed to modify the case).
Step 3: Add the Voltage Regulator
It is highly recommended to use a SMD (surface mounted device) part, as there is rarely any space in this freaky small piece of plastic...
Warning! Your part might look exactly the same as mine but you really need to check the pinout using a datasheet you get from your part vendor! The regulator must have a GND or - pin (black in my picture as connected to GND), a Vin or +in pin that goes to the red wire of the USB pin (the 5V from the PC) and a Vout or +out pin that connects to the +3.3V pin of the PCB (blue in my picture).
Note: You do not need to connect the tab of the regulator, it won't warm up seriously and you don't have to glue the part as the case will gently press it down.
Step 4: Close the Case and Enjoy
I had to remove some area of the bottom half for the connector.
Finally tape the thing so it won't fall into parts again (I used normal transparent tape). You can also glue it but you should take into account that you will void the possibility of servicing the unit again and that you might damage the PCB with the glue.
This tutorial ends here. Have fun and enjoy accessing the holy world of xbox's XTAF file system. I think I will make another instructable about using the unit with a PC (drivers, tools and stuff).
Remember: This will void your guarantee, but it will guarantee you much interesting insight in your game console system and enables you to share savegames and stuff ;)