From LiVEJOURNAL, a blog entitled A Culture of Transparency, a really good discussion of the value of (and really, the need for) transparency in business.
We discuss current problems on a mailing list. We post code reviews on a newsgroup. We skype with our offshore partners. Best of all, we use Confluence, a wiki-based system for design documents, test plans, task lists, FAQs, etc.
There are many other examples out there where Confluence is being used for these types of projects, a handful of which are listed here. We also post documentation and get feedback from users on our own collaboratively edited and openly viewable Confluence documentation pages.