Shmuel wrote an article about the transit of Venus that is happening right now. He provides some useful (and humorously written) tips regarding what not to do.
We’re putting this before the section on how you can view the transit of Venus, because it’s important. Do not look at the Sun. Repeat: do NOT look at the Sun, whether during the transit of Venus, or at any other time. Do not look at the Sun while wearing sunglasses. Do not look at the Sun through exposed film. (Color film doesn’t protect your eyes. Properly prepared black-and-white film containing silver does, but a lot of modern black-and-white film does not.) Do not, for Pete’s sake, look at the Sun through binoculars or a telescope. Do not look at the Sun through a camera. Do not look at the Sun through polarizing film. Do not look at the Sun through CDs or other computer media. Do not look at the Sun.