Hey!
I am currently modding my X360. Once I'm done I don't want to open my box everytime I want to upgrade the drives firmware.
So I integrated a SATA2USB adapter in my box. Now I can access it from outside the case anytime. My X360 has a new USB plug - simply plug a USB cable in, connect it to the PC and there you go!
Tools used:
- 1 new SATA cable
- some pcs of 15cm. cable
- soldering iron
- hot glue
- SATA to USB adapter (the one that attaches to the back of your SATA harddisk. I got mine at Conrad [Frankfurt, Germany] but I guess you can buy those everywhere. Also, any other USB to SATA solution should do the job)
Before I write books on what I did I made a schematic:

The switch switches between USB and mainboard connection.
And here are some images of my installation:

Tried to have the platine standing but the DVD won't fit:



Enjoy! (and feel free to ask questions!)