UML Forum (www.uml-forum.com) is a virtual community and knowledge portal containing pointers to some official and semiofficial information.
We particularly like the set of UML tutorials written by key UML developers such as Cris Kobryn, Gunnar (gunnaro@morfeus.it.kth.se), Bran Selic (karin.palmkvist@enea.se), Morgan Björkander (morgan.bjorkander@ telelogic.se), and J.Warmer@klasse.nl. You’ll also find pointers to tool vendors, UML books, and conferences.