As we noted in a previous blog post, the lack of so-called "enterprise architect" edition in versions of Visio since 2007 is a pain. The Visio 2007 solution is decent - though it requires a specific version of .net 1.1, XP compatibility mode, and some custom .xslt. Visio 2010 has a great third-party Forward Engineering solution from Alberto Ferrari, which is really, really, really easy.
Install the codeplex project, install.net 4.0 if you haven't already, activate the add-on (not an obvious step) and you're done. It integrates into the Office 2010 ribbon and you're a couple clicks away.
Here's the project: http://forwardengineer.codeplex.com/
Unfortunately, this solution also doesn't pick up the "notes" for Visio, which would be click if created as Extended Properties, but I can't complain.
"All truths are easy to understand once they are discovered; the point is to discover them." -Galileo Galilei