Peter,
A colleague and I have been working with a wi-fi enabled handheld (Dell Axim x50v, Windows Mobile 2003) and a PDA/mobile phone (Palm Treo 600.) Readjusting the layout of your Moodle course will go a long way to making it viewable in a handheld or cell phone.
A quick adjustment is to just rearrange your site/course so there are no blocks on the left side. I haven't tried yet, but I assume modifying a Moodle template will also help, particularly with large text display of some of the headers.
Of the different course management systems, Moodle is the only one that works most of the time. One system has so many hidden frames that it exceeds the limitations of the browser. Another system, the frames are fixed making it very difficult to navigate.
I keep getting asked what it will be like 5 years down the road. Some say "3D virtual environments" which to me says lots of computing power and development that makes the digital divide even wider. I think it's going to be mobile elearning that can be delivered anywhere. Right now Moodle is the best CMS that adapts to current mobile technologies.
Cheers,
Bob