Via the 1Million Women campaign blog I have discovered a "seasonal produce guide" that lets you know which fruit and vegetables are in season and therefore the ones you should buy. Food that is in season will have shorter food miles, be fresher, be better for you and will generally be more enjoyable to eat.
I have been wanting a pocket size seasonal produce guides for ages and have started dabbling in creating my own, going so far in some instances at looking at when you should plant various crops and calculate their availability based on time till harvest. But, yippppeee, there is no need to reinvent the wheel and I have now printed out the Sustainable Table's version.
The one downside to this guide is that it has been produced (by the look of things) by people based in southern Australia. There is therefore some seasonal variation between the northern parts of Australia and the fruits and vegetables available in the fields in southern Australia, but at least it does provide a guide. It will provide you with some reference to what you should be able to buy and perhaps over time you can amend it to better suit your region.
Give it a go and let me know what you think.