Some digging by Polish site Spider's Web has revealed Apple's set up early forum discussions for today's announcements. Looks like we can expect MacBook Airs, iLife '11, and a mystery "reserved" product. Mr. OS X Lion, we presume?
It does make you wonder whether the leak was intended. If it was indeed some Apple employee getting a headstart on the day's work, surely s/he would've just gone ahead and typed "OS X Lion," rather than "Category: Reserved 10 20." Unless he wasn't informed of what the product would be? We all know how secretive Apple is, especially with staff.
For the full story of how these products were discovered, check out Spider's Web site for the deets. None of the leaks are entirely unexpected, it's merely confirming what we'd already heard. [Spider's Web—Thanks, Michał!]
UPDATE: Our intern Adam raised the very good point of the 11.6-inch MacBook Air possibly having a new name, hence the discussion was labeled "MBA need official name." Something like MacBook Air Nano, perhaps?