In August 2003, August 2005 and now apparently in August 2006 an e-mail has made the rounds claiming Mars will be as big as the Moon. What's worse is its basically the same e-mail with just the year changed.
It is false, even when it was the right year.
Mars was pretty close in August 2003 - even a bit closer than in 1971, however the difference is tiny over the average, the Hubble Space Telescope wouldn't even be able to tell the difference. After all it was still 35 million miles away!
This year its actually completely wrong, the e-mail couldn't be any wronger. Mars is about as far away as it can get, its on the other side of the Solar System behind the Sun!
Mars will never, ever appear as big as the Moon, ever, excluding any possible cataclysmic event in the solar system. Mars at its closest is only about 1/70th the diameter of the full Moon. To the naked eye it will appear a reddish star in the sky.
With a telescope it'll appear as a small red disc, with perhaps some white on either side (the poles) and maybe some dark features visible on its surface too.
Here's a picture of Mars (and Saturn) I took a couple of months back.
Mars is the reddish blob near to the left of middle, closest to the horizon, to its left and above is a brighter star that's Saturn. The two stars seemingly mirroring them to the right are the two bright stars, Pollux and Castor in the constellation Gemini.
That's the extent of which Mars (and all the planets really) will ever really look like with the naked eye. Impressive and very bright but still looking like stars without a telescope or powerful binoculars.
For a larger version of this image and my other photographys check out my gallery.
So to say again, no Mars will not, nor ever look as big as the full Moon. Anything claiming Mars will be the size of the full Moon (from the Earth at least) is a hoax.