What’s Steve Jobs got up his sleeve?

The World Wide Developers Conference (WWDC) that opens Monday morning in San Francisco would be a relatively obscure technical gathering of programmers and IT administrators - with sessions on “Advances in OpenGL” and “What’s New in Objective-C” - were it not for one thing.

Steve Jobs.

The keynote address that Apple’s CEO is scheduled to give starting at 10 am Pacific Time (1 pm ET) is perhaps the second most closely watched event in high tech - after the opening speech Jobs gives every January at Macworld.

In the audience at Moscone West’s main hall will be - in addition to thousands of developers (WWDC sold out for the first time this year) - hundreds of reporters, photographers, TV crews, venture capitalists, CEOs and maybe even a few celebrities from Hollywood and the music world.

What’s Jobs going to talk about? To paraphrase Donald Rumsfeld, there are known knowns and known unknowns. That is to say, there are things we think we know he’s going to say, and things we know we don’t know. Here’s a rundown:

3G iPhone. Except for a few short sellers on Wall Street, everybody who follows Apple assumes that Jobs will introduce a new iPhone that can send and receive data at so-called third-generation speeds. (In fact, so widespread is this belief that if Jobs doesn’t show up with the thing on Monday, Apple’s (AAPL) shares will get hammered before he leaves the stage.) Almost everything else about iPhone 2.0 are matters of little hard information and intense speculation. Is it thicker or thinner than version 1.0? Will it have a built-in GPS chip so it always knows where it’s at? Will its price be subsidized by AT&T and the overseas carriers? Will it go on sale next week or sometime later? If these questions weren’t still in play, there would be almost nothing to talk about next week.

The SDK. We know Jobs is going to spend some time discussing the so-called software development kit for the iPhone. We know because that’s one of the two main themes of the conference (symbolized by the bizarre image of two Golden Gate Bridges that decorated the e-mail invitation). The other theme is the Macintosh operating system; presumably the two are merging somewhere in Marin County, judging by the doctored photograph. The SDK will finally give third party developers access to the platform Apple has managed to build, as Jupiter Research’s Michael Gartenberg notes, without them. There’s a flood of new software for the iPhone and iPod touch ready for release soon as Apple gives the word - including programs that will allow IT departments, should they be so inclined, to integrate the iPhone into their enterprises the way Research in Motion’s (RIMM) BlackBerry is today.

.Mac. Even Jobs agrees that Apple’s $99-a-year suite of Internet services (Mail, Backup, iSync, iDisk, etc.) needs an overhaul, if only to match the online applications that Google (GOOG), Yahoo (YHOO) and Microsoft (MSFT) now offer for free. By tracking crumbs of information scattered in recent Apple software releases, some observers believe Jobs is set to replace .Mac with something called Mobile Me, or just plain .Me. Probably the single most effective thing Apple could do improve .Mac would be to emulate Google and give it away.

Another iPhone. Speculation that Jobs would introduce a so-called iPhone nano - a smaller iPhone at a more affordable price - has faded; the smart money has pushed this back to next January. However, as American Technology Research analyst Shaw Wu points out, there are good reasons to suspect that Apple will keep the first generation iPhone around, if only to have something to sell in those parts of Latin America - and parts of North America, for that matter - where where 3G coverage is spotty or nonexistent.

New MacBooks. Two weeks ago, Piper Jaffray’s Gene Munster put the odds of Apple introducing redesigned Mac portables next week at 60%. The other odds he gave - 80% by the end of summer - now seem more like it.

New Touchscreen device. Wu in report to clients this week said he’s learned that work on larger, 4-inch and 7-inch multitouch devices has “gone beyond the prototype stage” at Apple. He goes out on a limb and gives 50-50 odds that one will be introduced at WWDC next week.

Those are the key themes, but there’s plenty more to speculate about. If you want to dig deeper - in a suitably interactive way - come to WWDC with a copy of the 2008 edition of John Siracusa’s Keynote Bingo card, pasted below the fold. The rules are laid out in detail at Ars Technica here, but they’re pretty straightforward: put a token over a square if Jobs mentions the topic or says the word or introduces the speaker during the keynote. Cover five squares in an a row, and you get to stand up and shout Bingo!

Nobody’s won the game yet. This could be the year.

[Moscone West photo courtesy of MacNN.]