This document discusses open source alternatives to proprietary software solutions. It notes that voice over IP and unified communications technologies are driving many companies to upgrade their existing telephony systems. It then provides examples of popular open source solutions for operating systems, web servers, browsers, telephony/communications, databases, CRM, backup, productivity suites, and collaboration suites. One section analyzes data showing that Asterisk, an open source telephony solution, was the second largest supplier of PBX end points in 2008. The document promotes the benefits of the Switchvox open source PBX solution, including no vendor lock-in, enterprise features at an affordable price, future proofing, easy use, and providing many products in one solution.