I used this approach, but ran into a couple of problems.
I created a live USB stick of Ubuntu 8.10 and booted off that. Then I downloaded and installed the Dell aircraft manager application (it wasn't in the standard Ubuntu I used). Then I ran it and enabled the bluetooth. Finally, I shutdown and booted back into OSX.
All seemed good - I had the bluetooth icon in the menubar and paired it with my phone, searched for devices, etc. - everything worked. However, there were a couple of problems.
Firstly, I couldn't turn bluetooth off from within OSX. The checkbox for this in the bluetooth preference panel was disabled (in the ticked setting). Is this how it is for everyone, or is it broken for me?
Secondly - and much more importantly - I now couldn't wake up from sleep. I just get a black screen. I tried this a few times (shutdown, boot up, close lid, open lid) with the same result. Then I shutdown, booted into the BIOS, turned off bluetooth, booted into OSX and I could once again wake up from sleep. So it seemed that the inability to wake from sleep was, for me, tied into having bluetooth enabled.
It may be to do with having to change some settings somewhere to be able to wake from sleep. I've never had any problems with sleep on my Mini, so I never looked into the discussions on that. That's what I need to do next, I guess. But bluetooth isn't too big a deal to me at the moment, so a big investigation isn't high up my to do list.
Anyway, just to confirm that this approach to enabling bluetooth has worked for me (although with the issues I've just described).