I agree with a few of the answers but I don't think it means that women can't wear pants. I do think this verse is pointing more to homosexuality and cross-dressing more than whether or not woman wear pants or not. 

I do not believe that this would include just wearing clothing alone. After all, at that time EVERYONE wore dresses, NOONE wore pants. 

This verse expresses a God given principle. God created man and women, two uniquely defined genders with no grey area between. As His creation we are to honor the dignity of our own sex and not attempt to adopt the appearance or role of the other. Therefore we learn from this that transvestism and homosexual behaviour is not God honoring. In fact it is a sin against God and against human kind as we are created in His image, pure, holy, righteous, gender specific but as we live in a fallen world we need the blood of Christ, his forgiveness and the Spirit's enabling to live accordingly. 

changed on Thursday, January 29, 2004 8:49:28 PM

From the commentary section of the NIV: Probably intended to prohibit such perversion such as transvestism and homosexuality, especially under religious auspices. The God-created differences between men and women are not to be disregarded. ie leviticus 18:22 & 20:13. I don't know how else to explain this one. Maybe after a lot of prayer he may provide us with an answer.
God Bless you in your search 

God is saying that thou should not wear anything that pertain to a man. Rather it is a shirt or pair of pants. Pants pertain to men. Along with a man's shirts, shoes or etc.