The following are for general information and ideas. Your own garden design will be greatly influenced by the particulars of your local environment, house style, personal lifestyle, municipal regulations etc.
Queensland
Australia
Australian Garden Design A collection of articles about designing gardens, with particular reference to Australian native plants. Association of Societies for Growing Australian Plants
Garden Design Some general garden design advice from the Australian Plants Society, Victoria
International
Garden Design Lots of ideas for various gardens styles, from Brooklyn Botanic Gardens
Landscape Art in the DQ Landcsape design of the Diplomatic Quarter, Riyadh, Saudi Arabia. Saudi Aramco World magazine
If you're looking for more about individual garden styles (Balinese, Mediterranean, African etc,) or designers or suppliers specialising in those themes, start here: Garden Styles