If your not going to use a hyperlink and you want to dent the sheetrock you can roll your own tooltip. My thoughts though are if your asking then you might not want to get into it.
From the raw you would have to use API's such as CreateWindowEx, DestroyWindow, SendMessage, GetWindowLong, and SetWindowLong. This will get you a tooltip interface but you then need to build the ability to look at the properties of entities your cursor is hovering over (more APIs) and gather them into the tooltip text property (I'm speaking from a class object property I use to do this).
As you can see this isn't a 5 minute fix. The cool thing I like about it though is that you have the ability to use a rectangular or bubble tooltip.
Good luck,
Bob Coward
CADS, Inc.