There's a plugin called "pTypeConverter" that does it.
However, with something like Window Live Writer, adding to either a page or a post is simple.
I've not had a problem ranking either and doubt there is much of a difference if any at all.
It's all about how WP displays them, to Google they are just independent URL's with content. How the CMS manages them is likely neither here nor there.
Use whichever is most convenient. Like the poster above said. Static front page, About, Contact..easier as a page probably, but even that is not fixed in stone.
Scritty