CheckedListBox Class for .Net 3.0: where is it?

I am using a System.Windows.Forms.CheckedListBox, and went to MSDN to read up
on its methods. There I found that there is a new CheckedListBox class for
..Net 3.0, greatly redesigned from the one I'm using. I've installed .Net
3.0, but this newer control does not show in my VS 2005 toolbox. The one
that's there is for .Net 1.1. Both versions are in files named
system.windows.forms.dll, according to the documentation, and the 1.1 version
is in the GAC.

I would like to use the newer version, but I can't find it even after
searching my entire C: drive for system.windows.forms.dll. Any helpful
information will be appreciated.

Here is a description of the new one:
http://msdn2.microsoft.com/en-us/lib...edlistbox.aspx

....and here is the one I have in my toolbox:
http://msdn2.microsoft.com/en-us/lib...ox(vs.71).aspx