I've created a modal dialog for a simple app I'm writing, so I've
knocked up a quick blog post pulling out the basics of the modal
dialog here:
http://dartwatch.com/index.php/2012/02/modal-dialog-in-dart/
Hopefully it will be of some use.
As a side note, I think that it should be easier to attach CSS to the
dom by creating a new instance of a Stylesheet class (but I don't
think it's possible to do that yet).
Cheers,
Chris