As Spring came, Trolltech has released a cutting edge betas of its primary products, introducing full Windows Vista support, a new scripting engine - QtScript (a successor to QSA) and improving many of the existing technologies that provide new or extended functionalities:

• streaming support to XML structures,
• secure networking through SSL sockets,
• improved OpenGLsupport,
• improved Main Window infrastructure,
• enhanced file system support through QDir,
• perspective transformations,
• improved widget styling through stylesheets
• and many others.

More info available in the official announcement as well as in a blog note on Trolltech Labs.