You should be warned that each variant of Flashback is very different, and very insidious. They will all inject malicious code into a variety of apps, and some of them will disable the built-in anti-malware protection in Mac OS X. Some will refuse to install if third-party malware protection is installed, others will disable that protection as well. And since there is absolutely no agreement among the various anti-virus companies as to a name, we have no way of knowing which variant it is that Sophos is calling OSX/Flshplyr-A.
Your symptoms may have resolved, but you may still be infected. Which means, you may still have malicious code in, say, Safari, snooping on your surfing and reporting back what it finds. It's looking in particular for things like bank site passwords. My advice at this point is to erase the hard drive and completely reinstall the system and all apps cleanly, bringing only user data over from your backups. See Flashback infections becoming widespread.
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