on the LAMP computer open a web browser to
http://localnost. The default web page should open.
For other machines on your LAN, make sure http is open in your firewall on the LAMP machine, then LAN workstations should be able to access using http://<your ip>
If you are using virtual hosts, you'll need some kind of name resolution so clients can use a textual url to your server. I use dnsmasq for lan name resolution. You can also edit /etc/hosts on clients.