Object relations does work in 3.0. You can see it in action here at ez.no. The "last forum messages", banners and "latest news" are all embeded related objects.
If you take a look at the standard templates, full.tpl, you will see that there is a block for the related objects. This block will show all objects which is related to the current object.
Well, I actually did that, and I did it again just to ensure that I did'nt do any mistakes. It still is'nt working. This is (one of the) code(s) used...: