How can I use apache or nginx as frontend for a node app?

I'm trying to develop a Node.js web application, but my production environment-to-be is already hosting Apache/2.2.22. So I can't have Node use port 80, and I don't want my users to have to go to http://myapp.com:4000/.

Is there an apache module that does this, perhaps like mod_jk does this for Tomcat?

The same question goes for nginx.

mod_proxy can do that (for apache)

<VirtualHost nodejs.host.com>
    ProxyRequests Off
    ProxyPreserveHost On

    ProxyPass             /           http://localhost:4000
    ProxyPassReverse      /           http://localhost:4000
</VirtualHost>

will forward everything on that virtualhost to Node.js