First post, so be gentle.
Context - I'm doing some research into healthcare provision and I'd like to visualise the data. I'd like to be able to put these PCT boundaries

as an overlay to google maps and change their colours and so on to show data... I'm running osx and I'm fairly IT friendly, but I've got no idea where to start on this and google is sending me in all manner of different diagrams with language I'm struggling to get my head around. So I'm looking for any information people can give me on:
- Recommendations of tools that run on OSX that might help
- A general outline of the workflow I'm going to be going though
- Places where I could put the finished files in an open-sourcy way so that other people might be able to make use of them?
Thanking you all kindly in advance...
EDIT - should point out that I'm happy to trace the lines with a tablet if that's what it takes - doesn't have to be postcode perfect just as long as it's recognizable...