netmeg - 4:45 pm on Feb 20, 2011 (gmt 0)
I used m.example.com, it worked out well. Just moved that site to WP though, so now I'm using a plugin that does it all with CSS. I like that approach because it gives the mobile user the choice between the mobile version or the full version.
I spent months asking everyone I could think of whether it was better to force mobile users to a mobile site via a browser detect, and got just about 50/50 results between people who loved it and hated it. So this way, at least they get a choice.