A few people asked me about books on homosexuality. Here are three that I recommend:
The classic work on this topic is The Bible and Homosexual Practice: Texts and Hermeneutics by Robert A.J. Gagnon.
James R. White & Jeffrey D. Niell wrote what is probably my favorite treatment of it, The Same Sex Controversy.
Finally, Homosexuality: A Biblical View by Greg L. Bahnsen is available online for free.