http://pocket.pirillo.com/ - I recently started broadcasting my live stream in SD widescreen (720x404). Once I made the switch via the Ustream Producer software, the live feed was no longer available in the current build of Ustream's mobile applications. Moreover, I've been able to start pushing out a live video feed which doesn't require Flash! This particular HTML5 version of my feed is truly of much higher quality than its Flash counterpart (and you can do a side-by-side comparison of the two in Safari on the Mac at the moment). No matter, thanks to Jared Pasanar for explaining it all to the community!
Formats available: MPEG4 Video (.mp4)