Web Server Setup

Okay let me lay it out for you, I am trying to make my Ubuntu 8.04 server with a LAMP setup run as my web server on a SBS03 network. Simply so that I can run our CRM on it.
I shut down the SBS world wide web publishing service and placed the ubuntu on a static IP.
I am running Apache2 and I can’t seem to figure out how to make the CRM url accessible to other computers on the network. It is SugarCRM and I I set it up to use port 81.
I am a noob so take it easy on me 😉 but I feel it is something simple I just overlooked.
Any advice is appreciated.
Thanks for your time