[>] .NET Framework XML Classes
This new suite of XML APIs is modeled after MSXML 3.0 and includes better standards compliance, extensible APIs, and a simpler programming model.
[>] FreeVBCode
This site is a large and well sorted collection of source code. The code pieces range from banal to excellent, and should satisfy all levels of expertise.
[>] Inside XML
Inside XML guides the reader through XML, covering everything you need to get up-and-running with an XML application. Except for good VB examples. The author decided to go with Java/Javascript -- a fair choice in itself, but it's not the right one for VB developers.
[>] Introducing XSLT
The XSL Transformations (XSLT) specification defines an XML-based language for expressing transformation rules that map one XML document to another. XSLT has many of the constructs found in traditional programming languages, including variables, functions, iteration, and conditional statements
[>] Microsoft XML Parser
Microsoft's XML parser and object model.
[>] Microsoft XML Web
An in-depth reference for Microsoft's XML component as well as articles and applications concerning XML.
[>] Professional Visual Basic 6 XML
James Britt and Teun Duynstee, the authors of Professional Visual Basic 6 XML, do a good job of outlining the XML universe. They guide you through the myriad of different standards, proposals, and just good ideas concerning the specification and use of XML.
[>] TurboPower XML Parser
[>] VB Web
An excellent site. The VB Web contains numerous tutorials on all flavours of Visual Basic development, with a vast source collection and well structured content.
[>] VB-2-The-Max
VB-2-The-Max is based around Francesco Balena, Italian VBPJ editor and regular VBITS speaker. The site is a tremendous resource for intermediate to advanced programmers, with lots of small tweaks and code samples you can utilize in your applications.

The site appears somewhat unstructured, but the search option remedies this in the usual way, so chances are good you will find any relevant items they have to offer you.

A splendid source for XML information. The site features an abundance of technical articles, books, and software, and hosts a thriving message board for XML discussions.
[>] XML Software
This site is probably the best resource for XML related software. It has an exhaustive index of all types of software you could possibly need, and the information seems updated and well kept.

You might get lost, though, if you don't know exactly what you are looking for, and there is no search engine to help you.