Until a few weeks ago, Tim Edwards was just another one of the men begging for change at a busy Houston underpass, ignored by most drivers who sped on past without a glance. Now, thanks to an Internet marketing campaign and unlikely allies, Edwards has become the human face of homelessness to thousands of online viewers drawn to his Web site by its deliberately controversial name — Pimp This Bum. During regular Webcasts, dozens of visitors to www.pimpthisbum.com/ ask questions about Edwards' life and his slow fall from office manager with a home, a car, and a future to an...