This one has been requested several times.
With the 0.75 release, there are some options:
First you can use Virtual Box (www.virtualbox.org) to create and run a virtual instance of Ubuntu on your mac.
You can then install SciDB onto that instance. It’s a bit slower but generally gets the job done.
You can also mess around with the source, get all the packages required for Mac OS and, after a couple of days of hacking you can get it to build and run on the Mac natively. I’ve heard it can be done and there are a few small source changes; most of the headache has to do with getting all the required packages to run on the Mac.
We’ll see what we can do to improve this in future releases.
Your comments, feedback, instructions are most welcome here.