The not-for-profit organisation aims to promote products and services to users. It plans to convince IT buyers that open source is a cost-effective alternative to packaged software.
The consortium was formed in the aftermath of the high-profile decision by Newham Council in August to opt for a Microsoft strategy rather than an open source one after a prolonged trial.
It also aims to counter Microsoft's advertising campaign that claims that open source is often more expensive than proprietary alternatives.
OSC executive director Mark Taylor said, "The open source movement is fast achieving definition as it evolves from the nascent fervour of its protagonists into a credible corporate alternative. That definition requires an independent voice.
"We aim to liaise with the UK and EU authorities on establishing clear guidelines to safeguard the ascendance of this exciting new alternative."
The consortium has already forged links with public sector IT managers' association Socitm, and the National Computer Centre.
OSC will offer four services: strategic consultancy, deployment consultancy, training and support. The group will look at several technical areas including the use of Apache and making websites accessible from open source browsers.
The consortium said it would not be competing with existing open-source organisations that are more concerned with developing standards.