Notice that many site front pages contain a main focus point, an area of content that switches through 4-5 different images or html content, like a preview teaser? Here is an example:
A Featured Products 'Showcase' with several tabs
* Blu-ray Players
There are other variations of this content slideshow online, but most of these are dependent upon fixed width DIVs and slide in and out of view, thus making them unsuitable for fluid layouts. However, this method with fade transitions rather than slide in is more preferable as it allows fluid layouts and variable width DIVs to fit in nicely without major problems.