Online search engine leader Google Inc. is wedding its instant messaging and e-mail services in the same Web browser, hoping the convenience will lure users from the larger communications networks operated by its chief rivals.

The new chat feature to be unveiled today will provide users of Google’s Gmail service with a list of contacts drawn from past e-mail exchanges and then signal who’s available for online conversations.

Automatic status reports about the online availability of friends, family and co-workers have been a hallmark of instant messaging services for years.

Google hopes to make it even simpler to connect with an online contact by allowing users to initiate an electronic conversation within the same Web browser showing an e-mailbox, bypassing the need to switch to a separate instant messaging application.