As widely anticipated, Google today launched its own instant message and web-based telephone system, in beta, joining a playing field of established rivals with more than 10 million users each - from market leader AOL, with AIM and ICQ , to Yahoo, Microsoft and Skype, writes Reuters. A trial version can be downloaded from www.google.com/talk; however, users must have a Google Gmail account. The computer-to-computer voice-calling software requires speakers and a microphone, or a computer-ready headset.

Google Talk also fits within the Google Sidebar, which was introduced this week and is designed to help the company branch out beyond search, allowing users to manage email, instant messages, news headlines, and music.

"This is a missing piece in Google's larger strategy…to become a bigger internet media player," according to Kelsey Group analyst Greg Sterling, who had been briefed by the company on Google Talk.

Attempting to turn its late-comer status into an advantage, Google Talk will allow users to communicate with other open systems. CNET writes that Google Talk is based on the Jabber open-source standard, which allows users to connect with other systems that use it, such as Apple's iChat, GAIM, Adium, Trillian Pro and Psi, as well as a system being test by EarthLink. AIM, Yahoo, Microsoft and Skype are closed networks that offer selective access

John Battelle is quoted by CNET as saying that IM is a "no brainer." "IM ties folks to a platform, and that's what Google is building with Desktop et al. VoIP is another possibility," he wrote in his blog.

"Hmmm…Google Talk; VoIP and IM. Since Yahoo and Skype also offer similar offerings I'm wondering what Google may do to spice up Google Talk a bit. You know, something that will Google-fy it," writes Search Engine Journal editor Loren Baker. "Perhaps…AdSense ads relevant to conversations which pick up the bill for VoIP to phone calls? Photo sharing and file sharing via the already available Google-owned Hello messaging program?"