Vodafone Australia has the Lumia 800 available (only in black unfortunately) on contracts starting at just $29 /mo (cheapest plan includes a $10 /mo handset fee). The Windows Phone, which was reportedly hitting Australia in all four colours - black, white, cyan and magenta.
While a strong choice of colour is not present at Vodafone AU, the Lumia 800 is a superb Windows Phone that has received positive reviews across the board. Should you be interested in cyan though, Optus is sporting this choice on their product list and at a more attractive price of just $19 /mo.
Source: Vodafone, Optus; thanks to the anonymous tipster!