sari42's suggestion works on any PC on which the "hosts" (note that it's hosts, not host) file is amended. It can be very useful for development work and in-house testing. My hosts file tells a story!
For a more flexible/dynamic solution, look at virtual hosting. Search this forum for that and/or "vhost" and you'll find a wealth of information.
Other reference material:
http://httpd.apache.org/docs/2.0/vhosts/