Hi Bob,
The ACCDW is an XML file that provides a link to the SharePoint site on which the Access Services site is stored. The ACCDW will default to download to your temp directory if you simply choose to open it. When you hydrate an application from the server, the default location for where you applications are saved is in "My Documents\Access Applications". In this folder you will find files with the name "Site on Server.accdb" that are the client databases.
ACCDWs are shortcuts only and, therefore, require that you are connected when you run them. However, the ACCDB client databases can detect that you are in offline mode and will allow offline editing of Access Services and SharePoint Data. Once you run the ACCDW once, you will have a copy of the ACCDB on your computer. We cache the SharePoint data locally when you are online using the application such that you can take it offline at a later date if you like.
If you're looking for content on how to use Access with SharePoint 2010, I'd suggest looking at the Channel9 Access Show or the Access Blog.
http://channel9.msdn.com/shows/Access/http://blogs.msdn.com/access/Regards,
Russell Sinclair
Program Manager, Microsoft Access
