The first release candidate for jQuery UI 1.8 is out and is live on http://jqueryui.com/demos/ . You can download it here:

Downloads
File Downloads
Development Bundle: http://jquery-ui.googlecode.com/files/jquery-ui-1.8rc1.zip

Svn
Tag: http://jquery-ui.googlecode.com/svn/tags/1.8rc1/

Changelog
See the 1.8rc1 Changelog for full details on what’s included in this release since 1.8b1.

Barring any catastrophic problems this code will become jQuery UI 1.8.

NOTE: If you’re using jQuery UI 1.8rc1 and you run into an error please make sure that you’re using the regular version (not the minified version) of the code, it’ll make it easier to spot where the error is occurring.

How can I help?
To start, try dropping the above un-minified version of jQuery UI 1.8rc1 into a live application that you’re running. Although, before doing so, make sure you look at the changelogs up to this release to make sure there are no potential conflicts with your code. If you hit an exception or some weirdness occurs immediately post on the Developing jQuery UI forum. Be sure to mention that you hit the bug in jQuery UI 1.8rc1!