Have a look a look at this link for vege. swap http://www.yesmagazine.org/happiness/matchmaking-for-vegetables
The idea is kinda similiar to the POW urban harvest days (the next one is Jan. 8 come along & check it out), or the informal sharing within community gardens, or over the urban back fence.
The sustainable Living Festival has an event where you can learn about organic food co-operatives – a western region success story
http://festival.slf.org.au/program/talk/start-your-own-organic-food-co-op
WOC & SOC website