Microsoft provides VB developers with control wrappers for the Windows common controls API -- an often used resource for GUI developers. The CCRP intends to replace Microsoft's wrapper with new and improved wrapper controls that impose fewer limitations on the programmers, increase our opportunities and ease our work.
All controls developed with the CCRP are free, but they have decided to keep their source to themselves. This shouldn't stop you from using their controls, though.
The Designer Widgets from Sheridan Software are known to many as the buggy control package. I have spent houndreds of hours working around problems arising with their controls. Not to say they aren't nice -- they really are -- but they are just too buggy.
A site that's off to a good start. The articles and code library are up and running, and contain some interesting items. A few points have been subtracted due to the very short descriptions of the various items.