You could try these avenues:

email phishing (at) cc.yahoo-inc (dot) com [email concealed]

and/or fill out the form on this page:

http://help.yahoo.com/fast/help/us/security/cgi_phishing

I doubt you'll get a personalised reply to any of those, though, but I
expect that they will deal with it.

[source: http://help.yahoo.com/l/us/yahoo/security/phishing/phishing-110143.html]

jv

On 7/13/07, Ryan Greenier <rgreenier (at) gmail (dot) com [email concealed]> wrote:
> Anyone have any good contacts for Yahoo to get a phishing site taken
> down? Apparently someone stole a credit card, registered a domain name
> & bought some space on a Yahoo web server in appearance of one of my
> company's clients. Nothing out of the ordinary, but what is out of the
> ordinary for me is that Yahoo is being less than helpful. Phone calls
> and email have done nothing so far. Anyone with any inside information
> on how I could get this taken down would be greatly appreciated.
>
> - Ryan
>

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