One of the new capabilities that has been featured in Notes 8 mail is the ability to have a vertical preview pane of your message. This feature emulates what has been found in Outlook for many years. As I was developing an interface for our contact management system, I discovered that this capability has been in Notes all along at least Notes 7 and most likely in Notes 6 and Notes 6.5. There are two critical factors to get this to work. First, you need to create a frameset that has two frames that has been split vertically. In the first frame, set the frame to the view that you would like to display.
Next, name the second frame to a given name that you would like. For example, "NotesPreview". Second, in the property box set of the first frame set "Default Target Links in Frame" to the name of the second frame.
As a result, when you click on a document in the view, a preview of the will be previewed in the second frame, vertically.