I do not think there are any international flights out of Canberra at the moment at all. The airport does have an international terminal, and in 2004 or so, the first scheduled international flights (that I ever heard of) commenced on a twice weekly basis to Nadi, Fiji with Air Pacific. The service seems to have been discontinued.
The airport is a reasonable size. It is shared with the RAAF (air force) and local and overseas government planes use the airport on their state visits. The airport's website has a pic of George Bush arriving in one of the president's planes - a 747 by the look of it, probably the famed Air Force 1.
Canberra is not so big (about 300,000 people) and it is only about 300km from Sydney, which has the busiest international airport in the country by far. Canberra's domestic flight operations are robust and so anyone travelling there from overseas would transfer at Sydney, or perhaps even Melbourne.
According to Canberra airport's website, there is a masterplan in place for attracting international flights. But with Sydney not so far away (in Australian terms), it will probably not attract international flights beyond a few leisure destinations, such as in New Zealand and other nearby Pacific islands like Fiji; and these would be by LCC's like Pacific Blue, the Virgin entity that operates between Aust, NZ
and a few Pacific islands; Jetstar (the Qantas LCC), who announced that they will commence international operations to NZ
later this year; and Freedom Air, Air NZ
's LCC subsidiary.
I wish the Canberra airport admin every success in getting international operations happening there - but I would not hold my breath even for the LCCs to commence int'l operations out of there in the forseeable future.
You might be interested to know that in the 1980s, Hobart (Tasmania) opened an international terminal at their airport. There were a few flights to NZ
, but it was later closed. I believe the particular terminal is now used by domestic LCC's. Hobart and Canberra are the only state/territory capitals with no regularly scheduled international operations.