The first public beta of Opera 9 web browser was released today,following a second technical preview of that was released about two months ago.

Opera 9 includes a feature called "widgets," which are small web applications such as newsfeeds or games that reside in a window on a user's desktop. It also comes with the BitTorrent file-downloading software built in, meaning users don't have to start that software as a separate application.

"There are no big feature changes in the beta version. The main difference is that the beta version is stable enough for people to use as their primary browser," said Tor Odland, a spokesman for Opera. A complete list of features is available here.

The software may still have some vulnerabilities in it, however, and Opera recommends that users backup their files in case any problems occur on their machine.

The software can be downloaded for free here. It is available for all major operating systems including Windows and the Mac OS, Odland said.

The final version of Opera 9 is due out in the next few months.