If you search for Teo Lachev and also Hitchhikers guide to Reporting services (first ones an author, the second a book by 2 guys who've written similar books for other tech's). I've used samples from both and found them quite good.
Also (if you can, i think it's public now) get your hands on RS2K5, the scenery changes a little with the introduction of ad-hoc query processing.
hth,