The latest release on the RBS CodePlex sample site (http://www.codeplex.com/sqlrbs) contains a sample application demonstrating the various ways to store and fetch blobs using the RBS interface. This includes basic store / fetch, specifying collections / blob stores for store calls, use of the push and pull streaming APIs, and an example that uses the System.IO.Stream APIs to do asynchronous reads from the blob store.
These samples have been designed to demonstrate best practices for using RBS, including correct Transaction usage, SQL connection information and BlobReference / BlobId optimizations. They require a database and client that has correctly installed RBS and installed a provider to run.
Feel free to leave comments or file CodePlex issues if you have problems or need assistance.