A new Powerpoint vulnerability and exploit have been developed (i.e., according to ISC, even on fully patched systems with MS06-048 installed). Users can avoid this by avoiding untrusted PPT attachments and staying up-to-date on AV protection until a patch is issued.
Microsoft PowerPoint 0-day Vulnerability FAQ
http://blogs.securiteam.com/?p=559
ISC - Trojan dropper in Power Point - a new issue?
http://isc.sans.org/diary.php?storyid=1618
TROJ_MDROPPER.BH
http://www.trendmicro.com/vinfo/virusencyc...EBH&VSect=T
TROJ_SMALL.CMZ
http://www.trendmicro.com/vinfo/virusencyc...CMZ&VSect=T