It will take a little less than seven hours for Venus to cross the disk of the Sun, with the entire transit being visible at latitudes above the Arctic Circle as well as in much of the Pacific Ocean, Australia, and eastern and central Asia. People in many other parts of the world, meanwhile, will have the chance to observe at least some of the event. In Western Europe, the final hour or so of the transit will be visible after sunrise on 6 June, whereas observers in eastern North America will be treated to the first two or three hours of the celestial phenomenon before the Sun sets this evening.Zz.
Edit 5/6/2011: There is a collection of websites on the transit of Venus, ranging from the historical perspective to why it is important astronomically. Check it out.