FYI, unless the (alleged) sender's domain has got SPF records and your mail server implements it, anyone can just change his 'From:' address to whatever he wants just by going to 'Settings...' in the mail client.
Actually bitcointalk.org *does* have an SPF record protecting it with a strict (-all) policy: according to standards, the phishing message should have been rejected, but your mail server probably doesn't enforce the requested policy.
SPF is a mixed blessing - as soon as you (legitimately) forward mails without completely rewriting the sender address, you get lost or rejected mails when you SPF handling is strict.
There's a workaround (SRS) which works mostly but makes some things unwieldy.
The other thing is that SPT does not protect the From: header (see
http://www.openspf.org/FAQ/Envelope_from_scope), so this kind of phishing would still be possible.
Onkel Paul