There is no doubt that Open Source software can save organizations significant amounts of money.  If Google, Yahoo, Facebook, YouTube were running on Windows, the licensing fees would be in the tens of millions of dollars.  These are enormous systems that are written by really smart engineers.  What about the small and medium business?  Money can be saved but some of the obstacles that prevent adoption of FOSS in the SMB market include:

• Get over the brand, i.e. Microsoft.  You can run FOSS in a Windows environment without problems.  Although you need to get around the mental/emotional/political hurdle of "Not being Microsoft" on the Microsoft Windows platform. 
• Staffing requirements.  If you have an IT staff that is resistant to change, or uncomfortable not running a well known "brand" software; you will have little acceptance.  FOSS software requires staff to be more motivated than traditional IT lifers.
• 80/20 rule.  FOSS software usually gives you about 80% of a complete commercial product.  The last 20% that provides UI polish and domain specific extensions rarely exist in FOSS.  If your requirements can fit into the out-of-the-box functionality - you are ready to take the next step.
• Black box is a good first start.  Finding applications and network services that can be drop-in replacements are prime candidates for switching over to FOSS.  Relational Database Management Systems (RDBMS) that are communicated using ODBC are almost always perfect first step.
• For more complex applications, the most important first step is developing a solid set of requirements.  Then, look for the FOSS that addresses all of your "Must Haves" and a good portion of your "Like to Haves".  This is not an easy process so you should consider working with an experienced company to conduct a "Project Scoping" workshop.

Hear more from Alan Runyan, co-founder of the open source Plone CMS, at Houston ITEC 2009.   http://www.enfoldsystems.com