How to test virtual host before dns propagation

Hi,

I think this must be a standard question & have searched groups but
could not find a similar one.

I have a VPS (Virtual Private Server), FreeBSD, Apache with faciities
& wizards etc. to set up virtual hosts. All works fine once the DNS
servers have propagated & I've set up a few mini-sites.

However I have a major site using PHP/mySql etc. that I want to move
from Shared Hosting but with my own IP to a Virtual Host on my VPS (&
only one IP).

1) I want to copy the site to a Virtual Host on the VPS & test it
before requesting the DNS change but I cannot see how to access a
Virtual Host via a browser when I have only 1 IP address.

2) Similarly when I do move it, I don't want 2 versions of my site
accessible as there is an updateable mySql server. When I had a
previous move from one shared Hosting to another, the ISP tech support
did some sort of redirect to force all visitors to go the new site
straightaway but I assume this was using the IP address. Now I have
VPS I have to do all myself. How do I do this please?,

Thank you.