Our latest stable release, Moodle 1.6.3, is now available for download from the Moodle Download page.
It mostly fixes bugs found since 1.6.2, with one in particular that is considered a serious security issue (note that all registered Moodle admins were directly notified of a fix for that problem on October 1). You can find out more details from the Moodle 1.6.3 release notes.