User Controls and how to use them

Hi All, I want to use user control to take care of controls that I use in more than one location on my applications. For example, if I have a drop down list that displays all the departments in my company, I would create a user control containing just the drop down list and bind data to it, then every time I want a list of departments in my company I would just drop the user control on to the page/form I am creating.  Is this the correct way to use a user control, or am I miss understanding the entire concept.Then, if I am correct, I need to know three mor ...