Just stumbled upon two articles by Teo Lachev which provide an excellent overview of the ReportViewer controls along with "real world" scenarios around how you can leverage them. The articles include some yummy sample code, too.
Find them here:
...and while we're talking about Leo: go buy his book on SSAS, pronto! I pre-ordered it and haven't had enough bandwidth to read it until recently...I'm glad I've found the time: it's a great read!