Good catch, exactly why I love slashdot.. the original quote starts with:

"ON the morning of September 13, 1985, Air Force Major Doug Pearson smashed through the sound barrier in his F-15. Pointed almost directly upward more than seven miles above the Pacific Ocean, he tapped a little red button on the side of his control stick, and released a missile strapped to the belly of his plane. The missile blazed out of sight, leaving the earth's atmosphere quickly and reaching a speed of 13,000 miles per second. Pearson wondered if it would hit anything."
http://www.spacedebate.org/evidence/1245/

I did a quick google search and came up with a range of 15,000-24,000 mph for the ASM-135a ( http://en.wikipedia.org/wiki/ASM-135_ASAT ), the modified missile they developed for anti-satellite operations. That's the right number but wrong unit so I double-checked the original source (National Review), and it is wrong in the original scanned copy and OCR text. I even checked the next couple of issues to see if they ever printed a correction but nothing came up.