Most theologians agree that there are three kinds of Old Testament laws. Summed up well here.
The Old Testament Law
Ceremonial Law: This type of law relates to Israel's worship. (Lev 1:1-13) The laws pointed forward to Jesus Christ and were no longer necessary after Jesus' death and resurrection. Though we are no longer bound to them, the principles behind the ceremonial laws, that is to worship and love God, still apply.
Civil Law: This law dictated Israel's daily living (Deut 24:10-11); but modern society and culture are so radically different that some of these guidelines cannot be followed specifically. The principles behind the commands are used to guide our conduct.
Moral Law: The moral laws are direct commands of God. A good example are the Ten Commandments (Ex 20:1-17). The moral laws reveal the nature and will of God, and still apply to us today. We do not obey this moral law as a way to obtain salvation, but to live in ways pleasing to God.
Now these divisions in the laws are not actual, meaning scripture itself does not explicitly call a law one kind or another. The concept was derived from the teaching that the law was 'nailed to the cross' with Christ, and therefore, some of it no longer needs to be followed to the letter, simplistically speaking.
Thus, most Christian sects will say that the Christian must only follow the moral laws. What the actual moral laws are is hotly debated. One commonality, generally, is that many Christians consider most if not all of Leviticus as Civil and Ceremonial Law and most if not all of the Ten Commandments in either Exodus or Deuteronomy are Moral Laws. After that, they seem to be debated on a one-by-one basis.