Basically it means that in future, you may be able to access and download videos from Youtube to your mobile phone directly. However, you don't need to wait that long for uploading videos to Youtube.com from your cell phone.
This moblogging feature called, YouTube To Go, has been around since May 2006. Here's a quick recap:
To upload video clips directly from your cell phone or PDA to YouTube, you need to create a Mobile Profile on youtube. You will then receive a special email address where you can email the videos as an MMS Message. Very simple.
Alternatively, if you want to watch Youtube Videos on your mobile phone today, here's a workaround - download the youtube clip in FLV format to your hard-disk, convert to WMV or MOV using the free free Simplified Universal Player Encoder and then transfer this file to your video enabled mobile device.
Involves a series of steps but works. Read detailed instructions.