Tim Cook will have a lot on his plate Tuesday when he takes the stage at the Town Hall auditorium on Apple’s (AAPL) Cupertino, Calif., campus.

Leaving aside whether he can fill the shoes of Steve Jobs (he can’t), or whether the new products and services to be unveiled meet all the expectations (they won’t), he’s got some important business to conduct.

Here’s what we’ll be watching for:

• New iPhone(s). The arguments swirling around the questions of whether there will be one new iPhone or two, an iPhone 5 or an iPhone 4S, a larger screen or the same size, a body that is teardrop-, wedge- or iPhone 4-shaped have taken on almost religious overtones. In the past week, doubt has been cast on what had been the prevailing theory — a wedge-shaped device called the iPhone 5 — including by reporters who have been given pre-release iPhones under nondisclosure in the past. At the least we expect a successor to the iPhone 4 with a sharper 8-megapixel camera, a faster A5 chip and double the RAM (to 1GB). A new shape to distinguish it at a glance from earlier models makes sense, but what it looks like we haven’t a clue.
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  New services. iCloud is likely to get top billing, but given that Jobs previewed the new wireless syncing and backup service last June, we don’t expect many surprises on that front (except perhaps some start-up glitches). The other major software advance, described in detail by 9to5Mac‘s Mark Gurman, is an  elaborate voice-command system called Assistant that would replace the iPhone 4’s less-than-satisfactory Voice Control. The possibility that Facebook might finally deliver an iPad app  is also getting a lot of attention in the trade press, but mostly because the delay in delivering it is said to involve some high drama between Steve Jobs and Mark Zuckerberg.
• New leadership. Tim Cook will reportedly be running Tuesday’s meeting, which seems only fitting given that he finally has the CEO title he so richly deserves. Nobody knows more about Apple’s operations than he, and we expect he will lead off the event with a report on how the company is doing and where its products are headed (especially in the booming Asian markets). But as we’ve seen — for example at the Oct. 2010 Back to the Mac event — he is not the natural showman Steve Jobs was. We expect that he will leave the actual product introductions to others, much as Jobs did as his stamina waned. How Cook chooses to share the spotlight will be closely watched for signs of who’s up and who’s down in the new regime.