NASA Science News[1] reports: "Earth and Mars are rapidly converging. Relative speed: 22,000 mph. Contrary to rumor, Mars is not about to swell to the size of a full Moon, but there is something eerie and Martian to look for in the night sky next week."
You must have seen the "Two Moons email"—claiming that Mars will soon swell as large as the full Moon, and the two will hang together side by side on the night of Aug. 27th. "Mars will be spectacular," it states. "No one alive today will ever see this again."
This story originated in 2003 when Mars and Earth were closest for centuries. I recall the original article actually (more or less correctly) said that through a modest 75 x magnification telescope, Mars will look as big as the full Moon to the naked eye. It was then misread and the global urban legend was born.
The best view of Mars will be in December, but the present dust storms on Mars may give it even a redder look than usual. It will not be as close and bright as in August 2003 though.
Jorrie
[1] http://science.nasa.gov/headlines/y2007/21aug_hurtlingtomars.htm?list878554