Haochi from Googlified has a scoop on the mobile version of YouTube -- it's finally ready to go, but be prepared to pay a fortune if you don't have an unlimited data plan through your provider. The first screen you see makes sure you are fully aware of that fact -- it's too bad unlimited data plans, at least here in Canada, still run you around $100 a month.
YouTube Mobile is a data intensive application. We highly recommend that you upgrade to an unlimited data plan with your mobile service provider to avoid additional charges.
YouTube is really starting to broaden their reach by letting people get this content through means other than their main website. The service started as just a website, then they created an embedded video player for any website, now within the last couple months they have announced this mobile version for your phone and a partnership with AppleTV to even bring it to your televison. The only thing missing now is a dedicated Wii channel!
Haochi also mentions the new "YouTube Remixer" powered by Adobe Premiere Elements -- it's a fairly simple way to remix your videos by adding titles, captions, transition effects and borders without needing desktop video editing software. One thing is certain, they aren't sitting still -- they are definitely a moving target for anybody who wants to compete.