Note - in case you use Ubuntu 11.04 - you don't need to do this - it works out of the box already.

If a btusb module is loaded - unload it first with

sudo rmmod btusb

Download and install this debian package: btusb-dkms_0.0.1_all.deb

Install the extracted deb file. Problem is that this file is made for older kernels. So - all we do - is install it, and replace the btusb.c file later to avoid the error.
Install with

sudo dpkg -i btusb-dkms_0.0.1_all.deb 

Download the replacement btusb.c and replace /usr/src/btusb-0.0.1/btusb.c with it.

After that, run compile and install the new module in the terminal, using this as a guideline:

sudo dkms remove -m btusb -v 0.0.1 --all
sudo dkms add -m btusb -v 0.0.1
sudo dkms build -m btusb -v 0.0.1
sudo dkms install -m btusb -v 0.0.1
sudo modprobe btusb

Finally, restart the bluetooth service with:

sudo service bluetooth start

You can get rid of the dpkg error message by downloading the following file and copying it to /usr/src. Run sudo apt-get install -f to remove installer error message.

Note - the data and the code on this page has been copied from Mac Book Pro/Ubuntu Maverick thread, as I'm too lazy to remember the Link every time I have to fix it on my mac mini. So - Thx to the community for the info.