What is a transit of Venus?
When Venus passes directly between earth and the sun, we see the distant planet as a small dot gliding slowly across the face of the sun. Historically, this rare alignment is how we measured the size of our solar system. The view is like a front row seat to the transit method, by which we now find planets around distant stars.
When is it?
Observers in North America see Venus on June 5 around 6:04 p.m. EDT until sunset. The entire transit lasts over six hours. This will be the last transit of Venus to occur in your lifetime. Next chance: December 2117.
Where can I see it?
Slooh Space Camera will provide a live broadcast from worldwide sites - view online at http://www.slooh.com. Watch the global celebration unfold with expert commentary. Check your local planetarium or museum for live observing opportunities in your community.
This is going to be awesome people! Its a once in a lifetime thing!
**EDIT**
This is how you can see the transit safely! http://www.transitofvenus.org/june2012/eye-safety