Flashback checker runs the tests described in the F-Secure Bulletin:
http://www.f-secure.com/v-descs/trojan-downloader_osx_flashback_i.shtml

Note** This utility checks and reports the presence of Flashback malware, 
it does _not_ remove it!

No affiliation with F-Secure.

Supports 10.5 and up, PPC and Intel clients.
Juan I. Leon
April 6th, 2012