To do it, you have to remove two screws beneath the panel. On this picture of the rear they are marked with red ellipses.
Use a screwdriver to unclip the panel lock...
...and the panel is free to go.
This is enough if you just want to remove/replace the keyboard or add/remove/replace the wireless card (it's under the keyboard).
You will want to remove the battery, the hard disk and maybe also memory. That's all on the rear, and removing it is not a problem. You will also remove the display, but this is also not a problem.
Just remove the other screws. You will need to remove almost every screw you can find, in particular all on the rear.
When you finally remove all of them, the motherboard will still not go out easily and you will be afraid to use force. But you will have to use some force. Just don't forget to unplug the modem first. It's connected to the motherboard with a small wire. You can see it on this picture (the motherboard is already removed):
If you plan to switch it on to test it while disassembled, don't forget to enable the Remote Desktop Connection to this computer (and try it to be sure that it works - connect from another machine) before you start to disassemble it. If you do so you will be able to use it while disassembled: Just connect the hard disk, put the memory in place, put the battery in place and/or connect the power cable, plug in the network cable, and turn it on. Like on this picture:
... I hope it helps a bit.
Zoran Vučić, 2007.