I love Spolsky's blog. He has also written articles for Inc, such as the one on competition and strategy called Fire and Motion. In the article there is a great quote about how management for his company is not about employees quickly obeying directives.
The biggest problem is getting people to tell me when I'm wrong and to do things their way, because they're all smarter than I am.
Ah, there is the crux. They are all smarter than I am. This is true of my employees as well. Not that every idea they have is superior, some are no good. But certainly some of the ideas are good and all of them make me think and rethink. And how else can I learn about these good ideas, how else can I think and rethink without being told?
The approach that works best is to be approachable. That way people will be more comfortable voicing their thoughts, opinions, etc. In many cases, the idea that I'm wrong comes as a statement of "how about if you do this", and so I pay particular attention to that kind of comment, as well as those regarding questions of why we do something the way we do.
It is of course important to show interest in peoples' ideas, even if at times they are no good. On the other hand, if I can't explain clearly why an approach we have taken is superior, then maybe it isn't, and at the least I haven't thought about it thoroughly enough.
Also, this should be a reminder that the people who will work best in this environment need to want to express ideas and to want to understand the organization, the customers, and the work we do.