U.S. Citizenship and Immigration Services has withdrawn the June 2008 version of Form I-9 and has reinstated the June 2007 version, but with a new expiration date of 30 June 2009. Departments should start using the June 2007 version with the June 2009 expiration date immediately.
Other than the revision date, there are no differences between the two versions. The form is available at http://www.uscis.gov/i-9, as well as on the International Faculty and Staff Services web at: http://www.ohr.wisc.edu/ifss/i-9/I-9.html. The link on the IFSS page goes directly to the USCIS web so the version that is on the IFSS web is always the latest version.
USCIS has stated that employers who used the June 2008 version while it was in effect will not encounter any difficulties. They simply want everyone to use the June 2007 version with the June 2009 expiration date.