I wrote a few articles at SQLServerCentral.com recently. It was a series of 4 articles which presents an XML based solution to the classical problem of saving a header/detail data entry form by hitting the databse server only once. The first article presented the basics of the approach and each installment there-after discussed more and more advanced stuff.
The discussion started with using an XML buffer to pass the variable number of item details to the Stored procedure. Then we discussed using XML nodes as well as attributes. The last article introduced the XML data type of SQL Server 2005 and a few XML processing functions.
You can find the articles here:
Hope this helps