I'm pretty sure Airport will work fine with Telstra BigPond cable, as will most other Wireless Routers.
A few points to remember:
802.11g (Airport Extreme) is faster than 802.11b (Airport) though which you will be able to use depends on the type of Mac you have and/or are planning to add to the network later.
802.11a does not work with Airport or Airport Extreme. You CAN get 802.11a cards for your Mac, but there isn't any advantage to doing so.
I'd recommend getting the appropriate Apple Airport card for your Mac, and checking the swapmeets for Wireless routers, though Apple's do represent pretty good value for money and are a lot less hassle to setup.