A few days ago I read C.J. Mahaney's Sex, Romance, and the Glory of God: What Every Christian Husband Needs to Know. It's a little book (125 pages counting everything) and I was very pleased with it.
I heard C.J. talk on the topic at a conference in 2004, which was very good. The book is a nice compliment to that talk. It is biblically helpful as he spends a little time in Song of Solomon, and it is gem on practicals. There are some things he suggests (no, not positions) that I have started to use.
If you are a married man and want to think about how to make your wife feel special, this is a quick read that has enough substance to chew on for a while.