I got a brand new A3 2009 model in Sept 2008.
I have the TDI 1.9L 77 kw / 105 hp(pk)
I have 13000 km now and my fuel consumption is no way near the officially indicated 6.6/4.4/5.1 l/100km.
the 5.1 (liter per 100 km) is average combined (or just above 45 mpg according to this site : http://www.american-car-net.com/us-mpg-lkm.aspx )

I drive like an old man... I eco-mile... I brake on the engine as much as possible...
I hardly accelerate (and have no fun)
and yet... on a freeway trip with no AC on and cruise control on... the best I get is 5.4 Liters / 100 km, where my usual mix of freeway and city driving gives me around 6 liters / 100 KM (or 39 mpg)

would like to know what sort a mileage another 2009 A3 1.9 TDI drivers are getting ??
(my previous Volvo 2.5TDI did better !)