[Doc].Bookmarks([BookmarkName]).Range.Information(wdVerticalPositionRelativeToPage)
Where [Doc] is a reference to the document you're working with (eg
ActiveDocument), and [BookmarkName] is a string literal or variable.
>I want to determine the vertical position of a bookmark (i.e., how far it
>is from the top of the page).
>
> How is that done?