Scroll bar (Floating, Changing Sheets)

[art]

Hello all:

I would like to make a scroll bar that would change sheets. That is, if the
user scrolls down to 15, then it goes to sheet number 15. However, I need a
few things. First is it possible to make the scroll bar floating so that it
always stays in view even when selected a different sheet.

Also (which is related to question 1), I want the sheets to change while the
user scrolls up or down. E.G. Scroll starts by 0, user scrolls down to 3, so
the sheets should jump from sheet 1, then 2. then 3.

Please help.

Thanks.