Just received this update from SpaceWeather.com:
Comet McNaught is plunging toward the sun and brightening dramatically. It is now visible to the unaided eye both at sunset and at dawn. Amateur photographers have found that they can take pictures of the comet using off-the-shelf digital cameras with exposure times less than a second. Estimated visual magnitude: between 0 and -1.
To see Comet McNaught, a clear view of the horizon is essential. In the morning, go outside and face east. The comet emerges just ahead of the rising sun. In the evening, face the other way–west. The comet pops out of the western twilight as soon as the sun sets. Binoculars reveal a pretty, gaseous tail.
Northern observers are favored. The long, dark mornings and evenings of Canada, Scandinavia and Alaska are ideal for viewing this comet so close to the Sun. But the comet has been sighted in other places, too, as far south as Kansas in the United States and Italy in Europe.