Last night, build 4029 of Microsoft's next big thing, Windows code-named "Longhorn", was leaked to the web by the folks over at #betas. Despite for the fact that it was compiled back in June, this is still the latest milestone-build of Longhorn that ever surfaced outside Microsoft's campus.
The most noticeable changes compared to the previously leaked build 4015 are an somewhat enhanced sidebar as well as minor improvements that have been made throughout the Plex-skin... Sorry, no Aero-skin yet.
News source: ieXbeta.com