Asteroid 2007 TU24 will miss us by about 530,000 km (334,000 miles) on January 29, 08:33 UT. NASA says it is about 150-600m Diameter and will be close to 10mag.
Bad Astronomy link
http://www.badastronomy.com/bablog/2...stance-update/
Orbit Simulation (very cool)
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007+TU24+&orb=1
NASA Report
http://neo.jpl.nasa.gov/news/news157.html