Queensland's flood worries aren't yet over, but the biggest long-term challenge will be rebuilding local communities. If you want to volunteer goods or services to help with that, the Wikifloods site provides a handy means of doing s.
Based on a similar site set up for the Victorian bushfires of 2008, the site lets individuals and businesses list goods which they're willing to donate, while people affected by the floods can list their needs and make requests from the donations already listed. Doing that should, as the site says, "allow donors of goods and services to be matched with those in need in a way that won't be a drain on the resources of the various authorities". If you want to help out fellow Aussies who have been struck by this natural disaster, this is a good way to get started.(Of course, cash donations to the Premier's Appeal are very welcome too.)