http://distrowatch.com/table.php?distribution=scientific
'Scientific Linux 4.2 for i386 and x86_64 processors is out: "Scientific Linux 4.2 was officially released. We want to thank all those tested, re-tested, and worked with the developers. This release might have taken longer than usual to be released, but it hopefully is one of the more stable. Scientific Linux release 4.2 is based on the rebuilding of RPMs out of SRPMs from [Red Hat] Enterprise 4 AS, including Update 2. Its biggest improvement over 4.1 would be the new yum 2.4, Yumex (a graphical front end for yum), and the various yum plugins.'