FYI, the good folks at SANS (www.incidents.org) have been tracking this as well and there is at least a name now:
Most popular anti-virus scanners are able to detect these exploitative JPG's including BitDefender, Kaspersky, McAfee, Symantec and TrendMicro, identifying them as "Exploit-MS04-028" or "Bloodhound.Exploit.13" (Symantec).
For SNG here are a few links:

http://securityresponse.symantec.com...gdownload.html
http://securityresponse.symantec.com...jpegshell.html
http://securityresponse.symantec.com...xploit.13.html
http://xforce.iss.net/xforce/alerts/id/182 (vulnerability and sensor info)