Sahil Malik has a great series of posts on the Business Data Catalog, including code samples and step-by-step tutorials. Check it out on his blog here.

Incidentally, if you haven't yet looked at his book "Pro ADO.Net 2.0", you may wish to pick up a copy. I bought one last year and have found it indispensable. It's easy to read and really gets into the details on not just the technical matters but the best practices and the issues you need to think about when working with data sources. I've already learned a lot from it.

One of the nice things about the Apress books is that they offer PDF versions as well, which is handy when you don't want to schlep dozens of hefty .NET books around.