<p>I can't seem to grok the concept of "loose coupling." I suppose it doesn't help that the word "loose" usually has a negative connotation, so I always forget that loose coupling is a <em>good</em> thing.</p>

<p>Will somebody please show some "before" and "after" code (or pseudocode) that illustrates this concept?</p>

Definition
Essentially, coupling is how much a given object or set of object relies on another object or another set of objects in order to accomplish its task.
High Coupling
Think of a car. In order for the engine to start, a key must be inserted into the ignition, turned, gasoline must be present, a spark must occur, pistons must fire, and the engine must come alive. You could say that a car engine is highly coupled to several other objects. This is high coupling, but it's not really a bad thing.
Loose Coupling
Think of a user control for a web page that is responsible for allowing users to post, edit, and view some type of information. The single control could be used to let a user post a new piece of information or edit a new piece of information. The control should be able to be shared between two different paths - new and edit. If the control is written in such a way that it needs some type of data from the pages that will contain it, then you could say it's too highly coupled. The control should not need anything from its container page.