Yahoo, in partnership with Symantec, has launched an internet security software suite, Norton Internet Security, that is designed to protect online users from threats such as viruses and spyware, the companies said today.

The suite includes Symantec's Norton AntiVirus and Norton Personal Firewall products. Yahoo users can try it out for free for 30 days, after which they can purchase a 12-month subscription for $50 (about £27), which the vendors described as a "special promotional" price.

Users can download the suite here. Yahoo will promote the suite on its websites, such as its search engine, and on its products, such as its browser toolbar.

Yahoo and Symantec have collaborated for years. For example, Yahoo uses Symantec security technology in Yahoo Mail, and the companies offer a co-branded browser toolbar.

With this deal, Yahoo is responding to a similar suite that rival AOL is now testing called Total Care, which includes technology from McAfee, one of Symantec's competitors.

The deal also increases distribution for Symantec, a timely boost after Microsoft launched its OneCare PC security suite in June. OneCare, which includes antivirus, backup, firewall, antispyware and PC tuning features, costs $50 for an annual subscription covering up to three Windows XP PCs.

Consumers need and want all the help they can get to protect themselves from the dizzying and ever-expanding variety of online dangers. Companies know that providing security services and products helps them retain users and attract new ones. It also encourages users to spend more time online, which is critical to Yahoo's online-advertising based business.