This one is the model i have. Twinhan VP7045A usb 2.0 digital HDTV TV tuner (great for laptops)
http://www.twinhan.com/product_terrestrial_7.asp
drivers 7045 (comes with driver cd too)
http://www.twinhan.com/download_driver&software.asp
Works under Linux Distros i have used it under Fedora Linux.
http://www.mythtv.org/wiki/TwinhanDVT_Alpha
http://www.linuxtv.org/
http://en.wikipedia.org/wiki/Video4Linux
Costs $35aud on special usually from msy http://www.msy.com.au
If you are unlucky to get it on special then it should cost about $85aud
It is best to buy an antenna cable and connect it into the wall socket for best picture 
also you will pick up more channels.
And you can record on to your computer hard drive (note you need a lot of hard drive space to do so and i mean a LOT!)