I currently work for Opscode who sponsor the Chef open-source project and supply commercial configuration management products.
I worked for Opsware Inc. a pioneer in the field of Data Centre Automation from May 2004 to July 2009. Including a short stay at HP who acquired Opsware in October 2007
Other previous employment (not chronologically ordered):
Aster Data: Now part of Teradata Corp.
Netuitive Inc. A Reston-based supplier of IT operational analytics software
VCE (the Virtual Computing Environment Company) formerly known as Acadia
Perot Systems Corp. Now part of Dell Services
Radan Computational: Now part of Planit
Digital Equipment Corporation (DEC): Now part of HP via Compaq