the only part of Leviticus still relevant in terms of being required now is the moral aspect, the ceremonial and legal aspects were fulfilled through Jesus.
In other words, the ceremonial practices (such as mixing seed, "clean" and "unclean," etc.) and the legal aspects (prescribed punishments, etc.) are not in force any more. However, the moral condemnations (homosexuality is wrong, murder is wrong, incest is wrong, adultery is wrong, etc.) are still in effect, given that the New Testament clearly affirms those.
No, really. It actually is that simple. Thus, homosexuality is wrong and should be condemned, BUT stoning them is no longer acceptable. The Old Testament law required constant obedience, and things like homosexual sex and murder were considered epic levels of disobedience, given how utterly and inherently unnatural (literally, perversion of God's intent) they are. However, thanks to Jesus' sacrifice, they can be forgiven - though forgiveness does require sincere repentance.