If one googles, you don't find much about WAP2 which uses XHMTL. Some useful addresses:
WAP Forum Releases
Documentation from Ericsson (PDF)
An Overview of Mobile Versions of XHTML
XHTML Mobile Profile
The Mobile Web Top 10
XHTML Tutorial

Interesting speech by Mr Ito;) - I didn't see the others yet...
See Nokia Connection 2004 Helsinki webcast

Joi finishes with the words (as noted by Jon):

"Maybe five to ten years from now, in this device, you will have every single song, that's available in the world. Your problem is not gonna be how to get the song. The problem will be: Which song do you want to hear?"

Via Joi

It's from last month and I didn't have the time yet to read Mobile Intelligence Tour to Tokyo

Mobile Trends Aim Toward Joining TV, FM Radio, 3G and E-Wallets:

The future may see digital satellite and terrestrial broadcasting being used to deliver media content, while cellular data channels are used for feedback, interactivity and marketing, since you can't send a signal back up to the satellite from a low-power portable device -- but you can send one to a cellular base station located a few blocks away.

The ideal solution is, perhaps, a cell phone bundled with a satellite receiver. There's no reason why clicking on a hotlink embedded in a broadcast TV program -- beamed from a satellite -- can't initiate a response that goes back to a broadcaster using a Java applet communicating via 3G cellular