I agree with jeroen; try adding a little lead based solder to the joint you're trying to desolder.
The reason we suggest this is because the XBox 360 uses entirely lead-free, RoHS-compliant, silver-based solder. That stuff melts at a higher temperature than normal lead/tin solder, so you have to get it pretty hot to desolder things off the board. Adding lead based solder will help lower the overall melting point of the solder joint.
thanks for the tip =D i've actually started making the laptop itself and so far i have finished all of part 1! now i need to find a place that sells pvc foam board......
Ive been looking around and reading the how-tos for the Xbox 360 laptop for a while now. I think im goin to try it! I just need to know where to get the same screen that was used in the instructable on Engadget. Also i dont want to buy a new xbox and was wondering if there was a place to buy old used cheap ones?