Q: What is Microsoft Office Communications Server 2007 Software Update Service?
A: It’s a web application for maintaining Office Communicator 2007 Phone Edition and MS RoundTable devices:
Heres what MS says:
Unified communication (UC) devices, such as Microsoft® Communicator Phone Experience and Microsoft RoundTable™, enable rich communication within an organization. Deploying these devices requires regular maintenance by the IT department, which includes providing available software updates to these unified communications devices. All UC devices rely on an automatic mechanism to obtain software update required on a regular basis. Microsoft Office Communications Server 2007 Upgrade Service provides an automated way to update all unified communications devices deployed in an organization. These software updates can be the latest enhancements or fixes to known issues in the current version already deployed on the device. This document guides you through the process of deploying the Office Communications Server 2007 Software Update Service in your organization.
The above link, points to the documentation, and is a good start to deploying this solution.