overall risk is 1:20000; closest approach, 1:26000. :') Here's a page from Italy:
http://131.114.72.13/cgi-bin/neodys/neoibo?riskpage:0;main
"More than 200 new observations of 2004 MN4 were obtained in the last 5 days. The discovery observations of June have been painfully remeasured, the impact monitoring computer programs have been run more than 30 times. Finally today some prediscovery observations from March 2004 were found and extracted from the archives of the Spacewatch survey. These allowed to extend significantly the observations time span, thus the confidence region for the orbital elements was sharply reduced and many impacts compatible with the previous data turned out to be incompatible with the extended observations.
"However, given the current knowledge of the orbit, we cannot yet exclude that there could be an impact at a later date, e.g., in 2044 and 2053. We have every expectation that further monitoring and further analysis on this object will entirely eliminate its potential hazard."
newest revisions:
http://neo.jpl.nasa.gov/risk/2004mn4.html
1 in 29,000 chance April 13, 2053
1 in 83,000 chance April 13, 2044