Google has equipped its Gmail online email client with support for the Google Talk instant messaging service.

The development allows users to use IM directly from the Gmail.com webpage, without having to download any client software.

While the service provides access to Google Talk's instant messaging service, users are still required to use the Google Talk application to place voice calls over the internet.

The new feature will automatically be added to Gmail over the next couple of weeks, with existing accounts upgraded in phases. The user will be presented with a new box labelled 'Quick Contacts' that lists frequently accessed contacts.

The service requires a browser window pointed at the Gmail service to be open at all times. It currently supports Internet Explorer and Firefox and requires the English Gmail user interface.

It also offers to log all IM conversations on the website and Google Talk application, and to search for conversations in the same way as for email messages.

Jon Perlow, a software engineer who worked on the project, claimed on Google's blog that this search facility will be a welcome addition. 

"My own chats contained a lot of important information that was always getting lost," he explained. "I found myself cutting, pasting and emailing important chats to myself so I could find them later."

Users will also have the ability to go 'off the record' by disabling a conversation from being logged by both parties.

Google introduced Google Talk in August. The application is currently in beta, as is Gmail.

The search firm is not the first to introduce a web-based chat client. Yahoo has a web-based version of its Messenger client, AOL has AIM Express for its IM network, and Microsoft offers MSN Web Messenger.

However, none of Google's competitors offers integration with the online email client or allows users to log conversations.