We hear Steve Jobs has tentatively agreed to appear on stage at the Wall Street Journal's high-profile D Conference for the first time in three years. The June event could be a major landmark in the Apple CEO's public recuperation.

Jobs first returned to a public stage seven months ago at Apple's Worldwide Developer's Conference, following a medical leave from the company. He's since led other Apple announcements, including the iPad unveiling in January. But D is a decidedly non-Apple event, and arguably the biggest business/technology conference going. It's certainly a pricey show—tickets cost $4,500—and other speakers addressing the assembled executives in Rancho Palos Verdes, California this year include Microsoft CEO Steve Ballmer, Facebook CEO Mark Zuckerberg, movie director James Cameron and AOL co-founder Steve Case.

An appearance at D would not only speak to Jobs' continuing physical vitality but also his willingness to address some of the thorny new controversies surrounding his company, including its newfound power over news media publishers and rival Adobe. At an Apple event, Jobs is in control; on a stage at D, he'd be fielding questions from the likes of the Journal's Walt Mossberg and All Things D's Kara Swisher.

Swisher would only tell us that Jobs has been "invited" to D and wouldn't comment further, but we've heard the CEO is slotted for the show but not 100 percent confirmed. If he shows up, Jobs' appearance would be his first at D since appearing on stage with his old rival Bill Gates, the Microsoft co-founder, in 2007.

Jobs' possible appearance isn't the only mystery Swisher and Mossberg are grappling with: The pair are widely believed to be negotiating a new contract with the Wall Street Journal to continue running D on behalf of the newspaper. Their prior contract dates back five years, to the days before News Corporation and its chairman Rupert Murdoch bought the paper. Murdoch can be a a notoriously finicky boss, but there's no evidence the hands-on Journal owner wouldn't want to cement the paper's relationship with Mossberg, a star Journal columnist said to make close to $500,000 per year; Swisher, co-leader of the widely-linked All Things D; or the D conference itself, a Journal crown jewel.

That said, email us if you've heard anything—either on Jobs or D.

Update, 8:30 pm ET: Jobs is now a confirmed guest, the D organizers have announced.

[Top Pic: Jobs and Mossberg at D 2007, by Asa Mathat, via D conference site]