The TechCrunch post on Joost for the iPhone came across my Twitter feed so I quickly launched iTunes and found the free Joost application. The application started up and looked promising on my WiFi connection, but I found the same issues that TechCrunch did with the application unable to play movies.
After launching Joost you will see a display with icons for Joost Picks (starts out here), Popular, Browse, Search and More along the bottom. I browsed through the films and tried to watch Starship Troopers, but received the Playback Error. I then took the advice of a TechCrunch commenter and restarted my device to play back the Men in Black Joost Pick, but again that video failed.
I then decided to try something shorter and launched one of the music videos. It started playing and then the audio cut out when I tried turning the volume down and the play/pause button flashed on and off. I paused it and then pushed play again and it ran for a while before then again cutting out the volume and seeing the video get very choppy.
At this time I can't recommend the Joost application, but there is potential for it to be a decent video solution on the iPhone. I don't have an iPhone 3G to test playback over a non-WiFi connection so I am not sure if it will work over 3G. I would much prefer to see Hulu on the iPhone since there are many more shows there I want to watch than on Joost. I also look forward to a Slingplayer or HAVA mobile client for watching my own TV content on the go.