Change Iceweasel identification

[mark <mark@neidorff.com>]

HI,

I'm running Lenny with Iceweasel 3.0.6. I understand that I can't 
upgrade the browser without upgrading to sid, which I'm not willing 
to do at this time.

Problem that I am having is that when I access yahoo mail, it tells me 
that in order to use the new version of yahoo mail, I have to use 
firefox (there are some other choices, but I don't want to install 
another browser).  

How can I have sites identify iceweasel 3.0.6 as firefox so that I can 
access the features of sites that are blocked from me?

thanks,

Mark