To get the hardware working on Linux:
install: bcmwl-kernel-source, bcmwl-modaliases
bcmwl needed to make wireless work. After install either reboot or remove sbb, b43 b44 and then load wl.
install: fglrx-amdcccle, fglrx-kernel-source, fglrx-modaliases, xorg-driver-fglrx
With the open-source graphic card driver the 3D Desktop does not work and more important the fan runs on full speed because the powermanagement of the graphic card does not work correctly. Restart X-Server.
options snd-hda-intel model=dell-m6
to /etc/modprobe.d/alsa-base.conf. Reboot or reload module.
Other hardware (e.g. camera) works out of the box.
Resume from Suspend does not always work (in ~4/5 cases it works). This is really annoying. Please write in the comment if you know how to fix that.
Keyboard: the sound volume special keys don't work.(https://bugs.launchpad.net/ubuntu/+bug/465250)
The suspend problem is still not fixed. This is very annoying. More details at: https://bugs.launchpad.net/ubuntu/+bug/391628
As I wrote their: I suggest to write to Dell. Hopefully there are enough people writing so that Dell lets ATI know they should fix it.