Thomas:
There's only one reference for Project VBA, and that's fellow MVP Rod Gill's
"VBA Programming for Microsoft Office Project Versions 98 through 2007. The
company I work for is the publisher. For more information see:
http://www.projectserverbooks.com
http://www.projectvbabook.com
Rod is teaching some courses this year, if you'd like to learn from the
master himself. For info on that, see:
http://www.projectservertraining.com
Beyond that, I caution you to be certain that your requirement to use linked
plans is absolutely necessary. IME, more times than not, taking this
approach is driven by corporate politics rather than what's best for
managing the process. If your project plans follow departmental divides,
efforts to deliver meaningful value from PM tools are likely to fail.