VBA will continue to work in Office 12 and for many years to
come.
All new version have new objects to learn, but legacy code will continue to
work for many years. There are WAY too many users/companies who depend on
the code they're writing now. MS can't "pull" it.
As an example of this, note that I can STILL open most all my old Word 6
WordBasic code and run it without problem in Word 2003. Granted,
occasionally some of that old WB code needs tweaking and attempting to
modify stuff like old custom dialogs without the benefit of having Word 6 or
95 installed to take advantage of the WB dialog editor tool is very
difficult...but they still work.
New coding alternatives will be showing up, such as XML of Word ML now in
Word 2003...but what you write today will continue to work for MANY years to
come.