Open Source Software ... what are the benefits of this to my business?

Cost savings
Open Source Software does not cost any money. It is not charged by license or by user. You can run it on as many computers as you want. Of course this provides a huge cost saving for businesses when considering expansion, hiring new employees, or simply making the most use of a tool across departments in an organisation.
Control over your Future
OpenERP software is not owned by anyone. So it cannot one day be purchased by a large organisation and discontinued, nor can key functionality be removed or changed (for example – Quickbooks 2007 and its lack of multi-currency support). And a company cannot simply give up on it (like Microsoft Accounting – software discontinued). So Open Source software protects the business who adopts it as you become part of the community and therefore you are then helping its existence. You also can get involved in the community and suggest new features, or enhance code with internal developments.
Lack of dependency
Open Source software also decreases your dependency on one or a few entities. Take for example Sage, you really need to contact Sage for support, code and bug fixes, and a host of other services that no other consultant or IT services business can provide. Contrastingly, OpenERP has a large group of global partners who can all work on your system with the same access as the main editor of the software OpenERP SA. This is not to say having a controlling organisation is a bad thing, actually we favour this structure heavily. Similar to the relationship between Ubuntu (Open Source GNU Linux based Operating System) and Canonical (private company), the OpenERP software and OpenERP SA organisation help strengthen and give a backbone to the application, thus providing additional benefits, security, resources, and value to companies using OpenERP.
Quality of code
It has long been identified that the quality of code is enhanced through Open Source. This is because the volume of resources available are far greater amongst the wider community who use the system as opposed to just a restricted group, as is the case with proprietary code. It is also considered to be more secure as flaws in design are spotted and patched quicker.