I have used several mobile video streaming applications on my S60 devices and keep coming back to Qik as my default client. Qik now has clients for S60, Windows Mobile, Java-based devices, and jailbroken iPhones with more clients coming. Last night they announced an alpha release for select BlackBerry devices, including the Pearl 8120/8130, BlackBerry Curve 8320/8330 and BlackBerry Bold. Support for the Flip is coming soon too. The BlackBerry you want to run this on must have BlackBerry OS 4.5 or above.
Most BlackBerry devices on T-Mobile and AT&T are just EDGE-enabled data devices so I would be interested in hearing people's experiences with it on these networks. Since they just updated their press release by stating they have support for the Curve, I will try this out on my Curve. My T-Mobile Curve also supports WiFi so I can test both EDGE and WiFi networks out to see how well it works with both. The BlackBerry Bold, with 3G support, is looking like a great new device that I might just not be able to resist. Make sure to read the directions for the Qik BlackBerry client since they are a bit different than the controls on other devices.