The US version of Business Week has published an article called "Knowledge Handoff" which discusses how corporations are scrambling to tap the expertise of baby boomers before they retire. The article provides relevant examples but in particular recommends "companies should encourage soon-to-be retirees to use digital tools like wikis, blogs, and instant messaging."
We have recommended to many clients that collaborative knowledge management, retention and re-use will provide an "organisational memory" that will be enduring long after their employees retire.