You know you're a geek when it's not even 7AM but you've already spent half the morning reading a whitepaper about Microsoft's plans to integrate XML and relational query language functionality into the .NET Framework with Linq.  C# 3.0 is going to be hot.

Like it's forefather X# Xen Cω, XLinq does an amazing job of integrating XML directly into the Common Language Runtime and the C#/VB.NET programming languages. Below are some code samples to whet your appetite until I can get around to writing an article later this year

1. Creating an XML document

   XDocument contactsDoc = 
       new XDocument(
         new XDeclaration("1.0", "UTF-8", "yes"),
         new XComment("XLinq Contacts XML Example"),
         new XProcessingInstruction("MyApp", "123-44-4444"),
           new XElement("contacts",
             new XElement("contact",
               new XElement("name","Patrick Hines"),                                       
               new XElement("phone", "206-555-0144"),
               new XElement("address",
                new XElement("street1", "123 Main St"),
                new XElement("city", "Mercer Island"),
                new XElement("state", "WA"),
                new XElement("postal", "68042")
                           )
                         )
                       )
                     );

2. Creating an XML element in the "http://example.com" namespace

   XElement contacts = new XElement("{http://example.com}contacts");

3. Loading an XML element from a file

   XElement contactsFromFile = XElement.Load(@"c:\myContactList.xml");

4. Writing out an array of Person objects as an XML file

   class Person {
           public string Name;
           public string[] PhoneNumbers;
   }

   var persons = new [] { new Person
                                                               {Name="Patrick Hines",
                                  PhoneNumbers = new string[]
                                                                                       {"206-555-0144", "425-555-0145"}
                                  },
                          new Person {Name="Gretchen Rivas",
                                      PhoneNumbers = new string[]
                                                                                       {"206-555-0163"}
                                  }
                         };

   XElement contacts = new XElement("contacts",
                           from p in persons
                           select new XElement("contact",
                               new XElement("name", p.Name),
                               from ph in p.PhoneNumbers
                               select new XElement("phone", ph)
                           )
                       );

   Console.WriteLine(contacts);

5. Print out all the element nodes that are children of the <contact> element

   foreach (x in contact.Elements()) {
               Console.WriteLine(x);
   }

6. Print all the <phone> elements that are children of the <contact> element

   foreach (x in contact.Elements("phone")) {
               Console.WriteLine(x);
   }

7. Adding a <phone> element as a child of the <contact> element

   XElement mobilePhone = new XElement("phone", "206-555-0168");
   contact.Add(mobilePhone);

8. Adding a <phone> element as a sibling of another <phone> element

   XElement mobilePhone = new XElement("phone", "206-555-0168");
   XElement firstPhone = contact.Element("phone");
   firstPhone.AddAfterThis(mobilePhone);

9. Adding an <address> element as a child of the <contact> element

   contact.Add(new XElement("address",
                 new XElement("street", "123 Main St"),
                 new XElement("city", "Mercer Island"),
                 new XElement("state", "WA"),
                 new XElement("country", "USA"),
                 new XElement("postalCode", "68042")
               ));

10. Deleting all <phone> elements under a <contact> element

    contact.Elements("phone").Remove();

11. Delete all children of the <address> element which is a child of the <contact> element

    contacts.Element("contact").Element("address").RemoveContent();

12. Replacing the content of the <phone> element under a <contact> element

    contact.Element("phone").ReplaceContent("425-555-0155");

13. Alternate technique for replacing the content of the <phone> element under a <contact> element

    contact.SetElement("phone", "425-555-0155");

14. Creating a contact element with attributes multiple phone number types

    XElement contact =
          new XElement("contact",
                new XElement("name", "Patrick Hines"),
                new XElement("phone",
                      new XAttribute("type", "home"),
                      "206-555-0144"
                ),
                new XElement("phone",
                      new XAttribute("type", "work"),
                      "425-555-0145"
                )
          );

15. Printing the value of the <phone> element whose type attribute has the value "home"

    foreach (p in contact.Elements("phone")) {
                if ((string)p.Attribute("type") == "home")
                    Console.Write("Home phone is: " + (string)p);
       }

16. Deleting the type attribute of the first <phone> element under the <contact> element

    contact.Elements("phone").First().Attribute("type").Remove();

17. Transforming our original <contacts> element to a new <contacts> element containing a list of <contact> elements whose children are <name> and <phoneNumbers>

    new XElement("contacts",
          from c in contacts.Elements("contact")
          select new XElement("contact",
                c.Element("name"),
                new XElement("phoneNumbers", c.Elements("phone"))
          )
    );

18. Retrieving the names of all the contacts from Washington, sorted alphabetically 

    from    c in contacts.Elements("contact")
    where   (string) c.Element("address").Element("state") == "WA"
    orderby (string) c.Element("name")
    select  (string) c.Element("name");

All examples were taken from the XLinq: .NET Language Integrated Query for XML Data  white paper.