ImageReady creates html pages, so all you really have to do is to open that new html page in Dreamweaver and you are set to go. When you click on Save Optimized in ImageReady it saves the html file using the same name as the original Photoshop file, then it also saves the images into the images folder (if one does not exist ImageReady creates one).
But this is not how I personally use ImageReady. I much prefer to create my tables or layers in Dreamweaver. What I do is to use ImageReady to slice the image and make the rollover images. It is also a great place to test the look of the rollovers. I then select File, Save Optimized As..., and save Images Only. This gives me the images and doesn't create the html page since I won't be using that. I then create a clean table structure in Dreamweaver and place the images into the new table manually using the insert commands in Dreamweaver. This is more work, and I frequently have to do some notes on a piece of paper first listing the sizes of my images before I build the table, but Dreamweaver gives me much more control over how the table is constructed, so that it behaves exactly the way I like.
I have found in general that it is often best to do things the long way with these programs and to bypass their quick solutions. I take ImageReady at its name, that it is a program designed to make Images Ready for the web, not to create final pages. You can create final pages and complete web sites in ImageReady, but the html code will not be as clean as what you would get if you did all your coding in Dreamweaver.
