MOUNTAIN VIEW, Calif. - Google Inc. is introducing new tools that will convert its free email service into a video and audio channel for people who want to see and hear each other while they communicate.

Activating the features, introduced Tuesday, will require a free piece of software as well as a Webcam, which are becoming more commonplace as computer manufacturers embed video equipment into laptops.

Once the additional software is installed, Gmail users will be given the option to see and hear each other without leaving the email application.

The video feature will work only if all the participants have Gmail accounts. It's supposed to be compatible with computers running the Windows operating system or Apple Inc.'s Mac computers.

Google, the Internet's search leader, has been adding more bells and whistles to Gmail as part of its effort to gain ground on the longtime leaders in free e-mail, Yahoo Inc. and Microsoft Corp.

Video chatting has long been available through the instant messaging services offered by Yahoo and Microsoft, but the feature isn't available in their free email applications.

Although Mountain View, Calif.-based Google has been making strides since it began welcoming all comers to Gmail early last year, it remains a distant third with nearly 113 million worldwide users through September -- a 34 per cent increase from the previous year, according to comScore Inc.

Microsoft's e-mail services boasted 283 million worldwide users, up 13 per cent from the previous year, while Yahoo was a close second at 274 million, an eight per cent gain, comScore said.