This phenomenon occurred last year (and in 2003), so this means that the next occurrence is in 2007, not this year. This e-mail is such a classic example of a hoax, that it is totally unbelievable that people still fall for this and distributes these lies to everyone they know. The e-mail states "This month and next, Earth is catching up with Mars . " It takes Earth 365 days to complete an orbit around the sun. Earth's orbital track is smaller than the orbital track of Mars, therefore it takes Mars longer to complete an orbit around the sun. Now explain to me how do Mars orbit around the sun twice in a matter of two months?
"Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again." It looks like the creators of this e-mail could not make up their minds about how long it will take for the next occurrence. The year 2287 is 281 years from now, almost 3 century's, now they suddenly speak of 60 millenniums. There are references to several scientific words and phrases in this e-mail that only a NASA scientist will understand, so how is it possible that they can't do simple maths while they possess the knowledge of an astrologist? NASA states that Earth has not been this close to Mars for the last 60000 years, I guess that is what got them mixed up.
"The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth . " Notice how they don't reference the year. This makes it extremely easy to use the same message next year and the years thereafter. It will be really silly if people forward this e-mail in September, but it is not impossible, people tend to miss little details like this because they read their mail like zombies, they don't always think about what they read. This is maybe the biggest reason why we get so many spam and chain letters forwarded to our inboxes these days.
"Mars will look as large as the full moon to the naked eye."
I guess once Mars looks as large as the full moon we should start worrying seriously.