I receieved this Question today:
"I am trying to rotate a form the same way it is done in PowerPoint. Are there any resources on MSDN that give some ideas on how to do this? I found some articles on how to rotate and flip an image but nothing on a form."
Today while you can draw non-rectangular windows using the Region property to make it look like the window is rotating you would still need to rotate the image inside that window...Pretty certain PowerPoint is not changing their Window shape but rather using something like Doublebuffering to draw/animate the Window, Graphics.BeginContainer/EndContainer to scope the rotating and Graphics.RotateTransform() to do the rotating.
Going forward Avalon/Longhorn will supply this functionality through XAML and the new storyboard controls.
If you really want to rotate your windows the GDI sample code below from the 101 sample collection changes the window into a circle which doesn't have a concept of top etc; so the orientation would be decided by what you put into it...
Dim p As New Drawing2D.GraphicsPath()
Dim bigDiameter As Integer = Me.ClientSize.Height
Dim donutWidth As Integer = 100
p.AddEllipse(0, 0, bigDiameter, bigDiameter)
Me.Region = New Region(p)