If you do not have a link to the Office Developer How-To Center, you should. At a regular basis, Microsoft is posting visual how-tos explaining in maximum 15 minutes a certain topic. Recently, a number of new additions were done:

• Creating Business Data Catalog Entities in SharePoint Server 2007
  Walk through building a Business Data Catalog metadata file that defines a simple LOB data entity.
• Retrieving an Entire Workbook or a Snapshot of a Workbook in Excel Services
  Get an entire workbook, a snapshot of the entire file, or just a snapshot of the viewable sheets or objects in the file using Excel Web Services.
• Filtering One Business Data Catalog List from Another by Using Associations in SharePoint Server 2007
  The Business Data Catalog allows you to define multiple entities for a given line-of-business (LOB) system. Furthermore, within the metadata file, you can create associations that define a hierarchy within the entities. For example, if there are two entities defined, such as customers and orders, you can create an association to tie the customer entity directly to the order entity. This allows users within your Microsoft Office SharePoint Server 2007 portal to create master-child behavior.