On Linux, Sametime will be available for Red Hat Enterprise Linux 4 and SUSE Linux Enterprise Desktop (SLED) 9 immediately after the launch, and SLED 10 soon after that, Marshak said.

Major IM clients that already run on Linux include AOL Instant Messenger (AIM), Gaim, Yahoo Instant Messenger and Skype. But IBM's Sametime is targeted at businesses, schools and governmental bodies that want to run Linux on the desktop, rather than hobbyist or individual users of Linux, Marshak said.

IBM's largest Sametime customer is a manufacturing company with 390,000 seats. It counts about 30 companies and organizations that each have more than 100,000 Sametime subscribers, said Marshak.