uZard is still in beta and the BlackBerry version is “uZard Web P“. From what I can tell (the site is not clear), I think this means that it does not use Webkit, whereas “uZard S” does. I could be wrong about that.
Anyway, I installed it and immediately went to the ArcGIS Resource Center to try the sample apps and they do run. The photo below is my BlackBerry Tour 9630 showing one of the Flex API sample apps from the Resource Center. They are a little hard to use but I suspect that’s because the apps themselves haven’t been optimized for mobile users. Nonetheless, the BlackBerry users kicking around San Diego this week may want to give uZard a try in order to test all the new Flex stuff that ESRI will be showing off.