Copyright vs Exclusive License

cdanzig writes: "My company recently hired a development house to do some contract work for us. They did great work, but they are claiming that they now own the copyright on the code and are issuing us a permanent and exclusive license. My bosses are concerned that this will hamper our ability to make changes to the code or prevent us form being able to claim the software as a company asset. What is expected protocol between a client and a development house? What is the long-term difference between owning a copyright and owning an exclusive license? If we paid for the development of the code is it fair for us to demand ownership?

-cdanzig"