You may remember Jeff Sandquist interviewing the Yahoo! Messenger team at CES this year (link here
if you missed it). This version of Yahoo! Messenger, which only works on Vista, has full animation using WPF. A public preview version of it is ready for you to download.
Features include tabbed conversations, drag and drop functionality (you can drag a contact to your Sidebar), enhanced emoticons, a slider that lets you adjust how much contact information you see, the ability to arrange your contact list into columns, spell check, and the ability to send files as large as 2 Gig!
Yahoo! Messenger now interops with Windows Live Messenger, including the ability to send files, so you can try it out without having to leave your Live IM friends behind.Download it here
and give it a try.