For a long time, the native YouTube app on the iPhone has stayed frozen in time. Though the website made a significant decision to replace star-ratings with a Like/Dislike rating back in March this year, successive iterations of iOS that have been released since then have not effected the change to the iPhone app.
That finally changes with the release of iOS 4.2. The new beta version of the upcoming iOS platform has revealed the arrival of the Like/Dislike button to the iPhone. Users viewing YouTube videos on their iPhone shall now be able to synchronize their Like database with YouTube videos they rate on the website or from other internet connected devices.
The new version of iOS is still not available for public download and so you may have to wait until November of this year to check out this new YouTube version.