MSP comes with some sample macros/VBA modules.  In
addition, there are several sites with VBA code.  
http://masamiki.com/project/
http://mvps.org/project/  (current broken VBA page, not
sure why)

And this site has information about the MSP Object model
(make sure to copy/paste the entire link):
http://msdn.microsoft.com/library/default.asp?
url=/library/en-
us/modcore/html/deconunderstandingprojectapplicationobject.
asp

That should get you going for now.  I'm sure there are
more, just do a search on Google.

HTH
--Jason