McDonald's has an external approach to an internal blog called Station M. It's for McDonald's employees worldwide and is available outside their firewall. Password protected, this makes it easy for non-wired employees (those who don't have access to a computer at work) to participate in the conversations going on at the site from their own computers or mobile devices on their own time.
Davey Rosenberg, a student blogger from James Madison University, has a great review of it over at his blog. Check it out.
Many companies struggle with blogs and other social media because of this very issue: allowing access outside the firewall. This McDonald's example is a good blueprint for how to do it without IT necessarily giving up control of the security of the corporate network.
What about you? Do you have other examples of good corporate uses for blogs and social media? Comments welcome, as always.