PHP, large content website performance

Hi all,

I work for a large publisher that has a pretty big presense on the web,
putting up some of their larger reference titles as subscription websites,
mostly to schools and libraries. I work as one of the software engineers on
these projects. Right now we use C++ to generate all our dynamic content as
CGI programs on Sun platforms. I find this to be overkill and we are
considering moving to a Linux based platform, and I would also like to use
PHP for our dynamic website development. However, I have to convince some
people in the organization that PHP is up to the task and has the
performance and stability for what we need. So, to that end I'm looking for
some feedback from the group in two areas.

1)  Where can I find some information on PHP's performance, both qualitative
and quantative?

2)  Where can I find some information (and sites) that provide a lot of
dynamic content linked together?

Thanks in advance for your help,
Doug Farrell