IBM is ready to plant a big wet kiss on Apple Computer.

At Lotusphere next week, the IBM Software Group is poised to announce updated Mac OS X support in the latest Notes client. In addition, the company will pledge big-time support for the new Intel-based Macs due later this year, sources said.

IBM’s Workplace Portal and Collaboration group, often known simply as Lotus, fields the Domino collaboration server, Notes client and Workplace portfolios.

The older Notes 6.5 client supports Mac OS 10.3 but thus far the current Notes 7 client has not. While Macs comprise a small percentage of business desktops, their users constitute a very vocal and influential minority, solution providers said. “Mac support for Lotus is a check-box item,” said Jim Murphy, practice manager for Strategic Computer Solutions, a Syracuse, N.Y.-based IBM partner. “We have a lot of health-care customers and maybe 1 percent of a company’s research department is on Macs but they have 99 percent of the influence.”

An IBM spokesman would not comment on the Mac plans, although in an interview late last week, Ken Bisconti, IBM’s vice president of Workplace, Portal and Collaboration products said to “stay tuned” for Mac-related news.

Industry observers say this newfound Apple love is actually a throwback to an era in which IBM and Apple collaborated on projects such as Taligent in the early 1990s. In that project, the two companies teamed up on “Pink,” an object-oriented operating system designed to take on Windows. It failed.

Some might say since Apple switched to Intel over IBM’s PowerPC chips last year, the two companies would be at odds, but they both face Microsoft on many fronts.

While not commenting specifically on Lotusphere plans, Judith Hurwitz, president of Hurwitz & Associates, Waltham, Mass., said she expects IBM to do all it can, once again, to marginalize Windows. “They do not want Windows to be the gate to everything,” she said.

IBM is also attempting an managed-client end-run around the Microsoft Office monolith.