COM and DCOM are the two new protocols that replace OLE and Remote Automation as MS' object sharing models.
As a programmer, you will see little or no difference with the two new object models. The only notable difference in Visual Basic 5.0 is the multiple choice Instancing property of classes. Earlier, a class was either Public or Private. Today, it can be a multitude of choices, all telling a story of what COM offers. DCOM replaces Remote Automation, but there is no difference to the programmer. It's only when you create the install files you will see the Setup Wizard ask whether this will be a DCOM application or a Remote Automation application.
[>] AndreaVB
An excellent site with lots of information. The content ranges from low level programming using the Windows API, to ASP and COM components. You might get a bit lost in the design, but focusing on the center white section of the page will help a lot.
[>] Applying COM+
Applying COM+ aims at uncovering the details of COM+ (and its predecessor, COM), explaining the platform on which COM+ components are based. For Visual Basic developers, this approach is somewhat counter productive, as Visual Basic itself hides COM's implementation details from the developer. Very little of what is covered in this book is accessible in Visual Basic today. Hopefully, that will change in the near future, and having read this book may prove useful yet.
[>] Edanmo's VB Page
This site is all about advanced source code.

The source code itself is outstanding -- VB source for custom controls you have dreamed about and system operations you've wanted to perform. On top of that, you get a bunch of free pre-compiled controls and time saving type libraries ready for use.

[>] Hardcore Visual Basic
[>] HOWTO: Configure DCOM for Visual Basic 5.0 Using DCOMCNFG.EXE
[>] HOWTO: Pass a Picture Object Remotely Using COM
[>] HOWTO: Port a Remote OLE Application to DCOM
[>] HOWTO: Use Win95 as a DCOM Server
[>] Microsoft COM site
Microsoft's main site about COM -- expect news, updates, patches, and new releases to be announced here.
[>] VB by JC
The author provides a small, but delicat set of articles and projects exploring advanced programming issues. The samples are well worth looking at just for the fun of exploration, and can serve you well if you are into this sort of problem.

With so few items, a search option would be inappropriate, and no points can be deducted on those grounds. The site is nice and well structured, so the only negative side is in fact quantitive.

[>] 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.
[>] Visual Basic Thunder
The site contains a lot of excellent source code relating to the Windows API. The code is well documented and illustrates dozens of useful procedures and methods. The downside is you can't search the site, so you are stuck with browsing the different categories to find the information you need.

Visual Basic Thunder is worth a visit if you want to check out new and cool ways to use the API with Visual Basic.