I would like to be able to port some new site pages over to PHP using the same db as in the coldfusion site. Is it possible to have PHP run pages in say other directory and
As others have said, its entirely possible and not hard to setup. Just watch out for Default Document as Adam Tuttle said.
I will take it a step further: you even run CF and PHP in the same application server!
Use Cauchos Resin for CF and its Quercus support for PHP:
http://quercus.caucho.com/
Of course, if your PHP app is non-trivial and/or relies on some custom extensions or extensions that Quercus doesnt support than your SOL. But might be interesting to check out.