Justin Taylor has collected some additional resources - audio, video, and print. He includes preliminary summaries of audio/video content which proves helpful in choosing what to watch or listen to.
The audio/visual lecture by Professor Sam Williams (Southeastern Baptist Theological Seminary) linked above is available in manuscript form here.
Justin Taylor says "If you’re looking for a good resource on thinking about the arguments for homosexuality—especially exegetical ones—the best authority to consult is Professor Robert Gagnon. His book The Bible and Homosexual Practice: Texts and Hermeneutics is the standard in the field."
A commenter on Taylor's blog post, recommended these additional talks.
Another commenter noted that Regent College Audio has an entire course (“The Bible, Homosexuality, and Sexual Ethics”) taught by RobertGagnon for sale. He says, "It is not cheap but it was well worth it. It is basically his “The Bible and Homosexual Practice” text in lecture form. 20 hours worth."
Additional note: On the subject of same-sex marriage, see previous posts here and here.