Convert ODT to PDF

We need an application to convert ODT (Open Office Writer documents) to PDF. We know this can be done using the OpenOffice client, clicking on the PDF icon, in batch, using an OpenOffice Macro or using the UNO API. We also know that OpenOffice only runs if X-Windows environment is installed. We need to perform this conversion from a PHP Script (wheter in PHP code, invoking a shell script or any other external application). If you bid on this project you should propose the development language to use (we prefer PHP). LGPL or BSD code can be borrowed, and the resulting project can be licensed as LGPL (not GPL as it will be integrated into proprietary software). Requirements: * OpenOffice doesn't have to be installed in the machine * X-Windows doesn't have to be installed in the machine * You can incorporate part of the OpenOffice UNO API is the licensing is adequate