The AT&T VoiceBuilder provides a new tool to researchers and practitioners who want to have their voices synthesized by a high-quality, commercial-grade text-to-speech (TTS) system without the need to install, configure, or manage speech processing software and equipment. It is implemented as a web service on the AT&T Speech Mashup Portal1. The system records, processes, and validates users' utterances, and provides a web service API to make the new voice immediately available to real-time applications. All the procedures are fully-automated to avoid human intervention.