In January of 2006, Jeff wrote a post about why Code Reviews are important and I agree 100% that it's the only way to improve yourself as a developer.
He also pointed to Karl E. wiegers book titled - "Peer Reviews in Software".

It's all about sharing and caring about your code and the product you are building.

You might ask what you should check for in code reviews?

• 1. Is it readable? Has the coding standards been maintained?
• 2. Determine what the code is supposed to do.
• 3. Determine what the code is currently doing and how it's doing it, is it doing it effeciently?
• 4. Have a look at the individual modules. If an object is called Person, make sure that the object describes a person fully and completely and only maintain a "person's" responsibility. Ask questions like, should this person object be able to make updates to a database or should there be a DatabaseContext object that handles this by accepting a person as a parameter. databaseContext.UpdatePerson(Person person);

The most value comes from talking to the other developer and learning from them and they might just make you realize that there are things that you haven't thought of. Libraries that might have made your life easier, reduced the time that you spent on writing a section of code.