We wouldn't elaborate for you more about this new. If you want to use Pre-Alpha Version of Yahoo Messenger, it also known as Yahoo Messenger 10 Pre Alpha Version (10.0.0.331), Just follow the links below to download it. It supports Windows Vista and XP.
Features on Yahoo Messenger 10 Pre Alpha: Multi Language Supported, Y!updates, Pingbox, Emoticons, and many more (just commonly had in other version of ym).
Download Yahoo Messenger 10 10.0.0.331 PreAlpha Version
Download Yahoo Messenger 10 at Rapidshare: Download