Yahoo is building better voice capabilities into its instant messaging software, replacing the current walkie-talkie technology with a constant connection.

Instead of having to take turns speaking, users will get good voice quality even if they're hooked up to the Internet at dial-up speeds, the company claims.

Both users will still need PCs equipped with a microphone and speakers, since the "calls" are made from within the Yahoo Messenger interface and there are no phone numbers to dial. For a fee, users can dial out to a phone number from within Yahoo Messenger using the third-party Net2Phone service.

Also new with the free service is a call history log and the ability to leave voicemail messages. "We have had PC-to-PC voice connections via Yahoo Messenger since 1999, and this is chapter two," said Frazier Miller, director of product management at Yahoo's instant messaging group.

Yahoo will do a test upgrade of Yahoo Messenger today, available at http://messenger.yahoo.com/.

Improving the voice communication capability of Yahoo Messenger is a good move, considering that VoIP is catching on thanks to improved service quality, widespread broadband adoption and the prevalence of PCs that come equipped with microphones and speakers, said Marcel Nienhuis, an analyst at Radicati.

Fine-tuning the product's voice feature also ties into the industry trend of extending IM communication's options beyond simple text messaging, Nienhuis said. "The nice thing about IM is that you have presence," he said, referring to IM services' ability to inform about people's availability status. "That's the heart of it, so it makes for a great platform to build other applications around it."

The new Yahoo Messenger beta also has improved photo sharing, including better image quality, a new interface onto which photos can be dragged and dropped, and the ability to grab photos from anywhere on the hard drive, whereas the existing version only allows the sharing of photos from a Yahoo album, Miller said.

Other types of files, such as Microsoft Word documents, can also be dragged and dropped into a Yahoo Messenger IM window to be transferred to another user.