Overall, the Bridge Workflow (now called LiveEdit although many components are still called Bridge) is pretty much the same as the CS 1 products and you should take a look in that section to refresh prior to reading these articles.
The biggest changes come in the form of a new file called an Assignments file (.inca). This file appears to be something of a scaled-down version (wireframe if you will?) of an InDesign file (.indd) and works as a way to control all the comings and goings of the system. From some basic tests I've performed, you can still use the old system of opening the .indd file in InCopy to perform edits, but I don't recommend it and I view this change as a good one despite some additional work overhead for the InDesign folks because it pulls people away from the InDesign file to a degree where I've seen some workflow problems develop in CS 1.
The other major changes come on the InCopy side of things, where a file you open in InCopy is no longer a .incc file, it is a .incx file which stands for InCopy Interchange Document. These are slightly different than the old files because they can contain the textual, story elements of an InDesign document as well as graphical elements and they are all grouped in to the Assignment files which allow control over who gets what. You can still perform the workflow the same way as I outlined in my CS 1 articles, but these new features allow more control and hopefully more stability as time will show. Toss in the fact that InCopy users can export files to RTF and there is a good deal of new functionality that is worth the upgrade.